Lacazette opened the scoring on 29 minutes with a fine touch and finish, but Fulham did get to the break on level terms courtesy of Andre Schurrle's deft 44th-minute reply.
That parity lasted only four minutes of the second half as Lacazette blasted his second into the bottom corner, and Aaron Ramsey increased Arsenal's lead 38 seconds after coming off the bench with the back-heel at the end of a silky team move.
Fulham capitulated in the final stages as substitute Aubameyang helped himself to two late goals, capping Arsenal's ninth successive win in all competitions in emphatic fashion.
Relive how the London derby unfolded with Sports Mole's minute-by-minute updates below.
11.00amAfter beginning his reign with two defeats, Unai Emery has led Arsenal to eight straight victories in all competitions ahead of the short trip across London to Fulham. A ninth win today would lift the Gunners, at least temporarily, into the top four for the first time this season. Let's get to the team news...
11.02amFULHAM: Bettinelli; Christie, Odoi, Ream, Le Marchand; Seri, Anguissa; Vietto, Schurrle, R. Sessegnon; Mitrovic Subs: Rico, Mawson, S. Sessegnon, McDonald, Johansen, Kamara, Ayite
11.06amBernd Leno makes his first Premier League start for Arsenal, deputising for Petr Cech who is out with a hamstring strain. Many expected the German to come straight in as number one following his arrival from Bayer Leverkusen in the summer, and now he has a chance to make his case.
11.08amThe goalkeeper is one of five players retained by Emery from Thursday's 3-0 win over Qarabag in Baku on Thursday. Rob Holding, Nacho Monreal, Alex Iwobi and Danny Welbeck, who gets an opportunity with Pierre-Emerick Aubameyang suffering from illness, all pull double duty for the week.
11.10amAubameyang is deemed well enough to be named on the bench, alongside Aaron Ramsey who was a doubt to feature with his wife due to give birth imminently. Mesut Ozil has been ruled out because of a back spasm so Henrikh Mkhitaryan gets his first league start since August.
11.12amYoung midfielders Matteo Guendouzi and Emile Smith Rowe each scored their first Arsenal goals in Azerbaijan in midweek. Guendouzi continues to play a role in the Premier League squad but Emery has said that 18-year-old Smith Rowe 'needs to earn the opportunities' for more first-team experience.
11.14amRob Holding makes his 50th Premier League appearance for the Gunners today, keeping his place despite Sokratis Papastathopoulos returning from a knee injury, and scoring in the Europa League. From a selfish point of view, I'm a little relieved the long-named Greek isn't in the starting XI today!
11.16amFulham boss Slavisa Jokanovic makes two changes to the team which lost 3-0 at Everton last weekend, both in defence and both enforced. Full-backs Timothy Fosu-Mensah and Joe Bryan have respective shoulder and hamstring injuries so Cyrus Christie and Maxime Le Marchand come in.
11.18amAlfie Mawson has recovered from a back injury but is only named on the bench as Dennis Odoi and Tim Ream continue in the centre of a defence which, following Brighton & Hove Albion's shutout of West Ham United on Friday, is the only one in the league yet to keep a clean sheet this season.
11.20amSpeaking about the defensive flaws that have blighted Fulham's start to the season, Jokanovic told BBC Sport: "We cannot be satisfied with this spell during this first seven games.
"It's huge room ahead of us to improve and we must try and work hard to fix all our problems. One of these is conceding so many goals and we are working in this direction to try find a solution."
11.22amThe Cottagers have the third worst defensive record in the league - behind only Cardiff and Huddersfield - having conceded 16 goals in their opening seven games. Jokanovic did not sacrifice his attacking beliefs against Man City and were rolled over 3-0. Will he have a change of tact today?
11.24amA Fulham defeat this lunchtime would ensure that this side equal the club's worst start after eight top-flight matches of a season, set most recently in 2005. The Cottagers did recover that year to achieve a comfortable mid-table finish of 12th, which is about where they have been tipped to finish come May.
11.26amHowever, Fulham have won just three of their last 30 top-flight games against the Gunners, losing 21 of those Their only victory in the past 11 meetings came at home in January 2012 when goals from Steve Sidwell and Bobby Zamora in the last five minutes snatched them a 2-1 triumph.
11.28amFulham's defensive fragilities go back a lot further than this season, at least when it comes to matches against their capital rivals. They haven't kept a home clean sheet in 14 Premier League derbies since beating Queens Park Rangers 6-0 in October 2011.
11.30amToday Jokanovic's men are up against the Premier League's London derby specialists, with Arsenal's 51.3% win rate in these fixtures the best in the division. However, the Gunners have only derby away win in the past eight attempts - at Crystal Palace last December.
11.32amA win today would mark Fulham's 300th victory in the top flight, and seven of those have come against the Gunners although Arsenal have won their last two league matches at Craven Cottage.
11.34amAleksandar Mitrovic has outscored Aubameyang and Lacazette combined so far this season, bagging five goals in his opening seven games. The Serbian has actually scored nine goals in his last 10 home league appearances for Fulham and is undoubtedly their danger-man today.
11.36amEmery has highlighted several Fulham players who Arsenal will have to keep an eye on today, telling BBC Sport: "Fulham bought very good players like Seri, like Anguissa, and they have Mitrovic and Schurrle too.
"Fulham is a very big challenge for us, first because it's away and second because each match in the Premier League is very, very difficult."
11.38amConfidence should be high in the Arsenal camp though and are now vying to win six successive Premier League matches within a single season for the first time since August to October 2016. They could also earn three Premier League away victories in a row for the first time in two years.
11.40amThe Gunners have kept successive clean sheets in the league, last achieving three in a row in November 2017. They do still look vulnerable at the back though, conceding more shots on target to Everton and Watford than they managed themselves in those respective 2-0 victories.
11.42amLucas Torreria's insertion into the starting lineup might have something to do with Arsenal's improved defensive record. The Gunners concede on average 0.5 league goals per 90 minutes when the Uruguayan midfielder is on the pitch, compared to 2.2 per 90 when he is not.
11.44amThe travelling fans need not worry if this game is still goalless at half time. Arsenal have scored 10 second-half goals in the league this season, a joint-high with Man City prior to the latest round of fixtures.
11.46amUntil Aubameyang's illness this week, Emery had found a way of getting both the Gabonese and Lacazette in his team - arguably Arsenal's best two players. That has come at the expense of Aubameyang's best form as he has been forced out to the left but the two have struck up a good relationship.
11.48amIn Aubameyang's absence today, Welbeck gets the opportunity to show why Gareth Southgate rates him so highly. The England international, making his first league start of the season, has four goals in all competitions this season and may be more comfortable in that wide role than Aubameyang anyway.
11.50amTen minutes until kickoff at the Cottage, where Emery's Arsenal will be tested in a new way today. This is the first time this season that they will have to deal with the hangover of a long Europa League travel schedule. Emery rotated heavily so will hope that his boys are fresh enough to not let it be a factor.
11.52amJokanovic has given himself the option of going with a back five today, with Le Marchand capable of operating in a central three and Ryan Sessegnon, yet to set the Premier League alight as expected, playing from wing-back. It might be something that the Fulham boss tries to tighten up his defence.
11.54amExpect fireworks from this one - there has been four red cards in the last four league matches between the two. We know that Mitrovic has a short fuse but there's a lot of Fantasy Football managers hoping that the Serbian can control his temper today!
11.56amA reminder that Arsenal can climb into the top four with a win today, at least temporarily ahead of Chelsea's trip to Southampton later this afternoon. A win for Fulham could lift them four places to 14th and take them five points clear of the drop zone.
11.58amPREDICTION: Arsenal do still have defensive frailties and have been lucky to get away with that in recent weeks, so I can see Fulham causing them problems. The hosts are even more leaky though so I am expecting a high-scoring draw - an entertaining 2-2.
1 minKICKOFF: This London derby is underway at Craven Cottage, where Paul Tierney is our referee this afternoon...
2 minSHOT! Mkhitaryan finds a little space in between the lines and takes on an early shot which he slices wide from 30 yards.
3 minSAVE! A slack pass from Bellerin is picked up by Luciano Vietto in the Arsenal half and the Argentine drives forward to the edge of the box, where he unleashes a shot which takes a big deflection off Holding. Leno reacts really way to the change of direction and pushes the ball away with a strong hand.
5 minThe hosts have indeed started with a back three and Arsenal are already looking to exploit the space behind the wing-backs.
7 minEnd-to-end stuff already, with Iwobi running into the aforementioned space and knocking in a cross which very nearly fell to Mkhitaryan, with Sessegnon doing just enough to clear and start a Fulham counter. Vietto aims for Mitrovic's run to the near post but Mustafi makes a crucial block.
9 minConcern for Arsenal with Lacazette down injured having been caught on the ankle by a Mitrovic trod. It looked accidental from the former Newcastle striker but those can be very painful.
11 minFulham have not quite settled into this new shape yet, with Iwobi once again getting down the left. Christie has the pace to get back and tackle the Nigerian and eventually the danger passes.
13 minAll of the action at the moment is happening on one side of the pitch, with Vietto heavily involved on the Fulham right and Iwobi likewise on the Arsenal left. Odoi, playing on the right of the back three, stands up well to an Iwobi dribble inside the area.
15 minChristie whips in a lovely early cross for Mitrovic but Mustafi intercepts before it can reach the Serbian, who will cause Arsenal problems if he continues to get that sort of service.
17 minThere is another injury stoppage, and again Mitrovic is involved clashing with Monreal in a 50-50. The Fulham man has walked away pretty unscathed but Monreal has a real limp on - something for Emery and his staff to keep an eye on.
18 minSeri tries dropping the resultant free kick onto the head of Mitrovic at the back post but again Arsenal win the initial header. The striker tries a spectacular volley, on his weaker right foot, with the dropping ball, and sends it sky high.
20 minGranit Xhaka - maligned by some sections of his own fans - is the Arsenal captain today in the absence of Cech, Laurent Koscielny and others. That does seem a bit of a strange decision from Emery given the experience and consistency that Monreal has given the club.
22 minGood awareness from Sessegnon to turn the ball around the corner on the volley but the execution is just lacking as the pass is out of Vietto's reach.
24 minFulham are doing just about enough to keep Arsenal out. Le Marchand makes an outstanding interception in his own six-yard box, with Lacazette ready to pounce on Welbeck's cross, and moments later Odoi comes up with a perfectly-timed tackle on the cover after Iwobi had skipped past Ream.
26 minSHOT! The Cottagers still possess their own attacking threat though. Schurrle takes on a shot from 22 yards which Leno gathers smoothly. The German did have options up with him but decided to go for goal and it was a decent effort on target.
29 minGOAL!FULHAM 0-1 ARSENAL (ALEXANDRE LACAZETTE)
29 minThe Gunners take the lead just before the half-hour mark, with Lacazette brilliantly finishing off a well-worked move. Fulham failed to heed the warnings of the threat from the Arsenal left, as Iwobi shifts the ball onto Monreal on the overlap and he crosses into the feet of the goalscorer. It is a great first touch from Lacazette, and an even better second as he swivels and shoots into the bottom corner.
31 minThat is only Lacazette's third away goal out of his 20 for Arsenal in all competitions. At the other end, Fulham look for a response as Anguissa drags an ugly shot wide from distance.
33 minCLOSE! Fulham are living very dangerously here, and again the chance comes down the Arsenal left. Christie is way out of position and Welbeck knocks the ball into the six-yard box where Mkhitaryan nearly bundles it over the line, with Le Marchand and Bettinelli combining to do just enough to keep it out.
35 minTorreira has been very efficient in this first half, winning a lot of second balls and using the ball well. The Uruguayan has taken a knock and needs medical attention but should be fine to carry on.
37 minSessegnon gets to the byline but his cross is too close to Leno and easy pickings for the goalkeeper at the near post.
39 minMustafi is peeling onto Sessegnon at the back post from all of Arsenal's set pieces and he is dominating in the air. So far it has not paid dividends but a second ball is sure to drop Arsenal's way at some point. That is the sort of unfashionable tactical detail that might have been ignored by Arsene Wenger.
41 minCHANCE! The boy Sessegnon is starting to have an influence on the game. He shows great awareness to intercept a pass from Leno aimed at Bellerin and then picks out a good pass inside to Schurrle, who lashes a rash half-volley over the crossbar.
44 minAgainst the run of play, Fulham grab an equaliser on the stroke of half time. Monreal's clearance is picked up by Seri who quickly releases Vietto. Schurrle makes a really good run across the defence and the pass is perfectly weighted for the German to deftly lift over Leno. Lovely finish - his 3rd of the season.
12.50pmThe half-time whistle blows with Arsenal having been pegged back by Fulham after having much the better of the first period. A well-taken goal at each end assisted by some poor defending.
12.52pmFulham's wait for a clean sheet goes on after Lacazette's 29th-minute opener. Jokanovic was given plenty of warnings, with Arsenal constantly getting in behind Christie down the left, but he did not react and paid the consequences. Still, the Fulham boss has not changed that vulnerable shape.
12.54pmThe Gunners could have been two or three up had it not been for a couple of vital last-ditch interventions from Le Marchand, and were then let down by the usually reliable Monreal whose poor clearance led to the equaliser. Albeit, it was a very skilful finish from Schurrle past his compatriot.
12.56pmSTATS: The half-time numbers suggest that this has been quite a tight game, with Arsenal only edging possession 51-49 and Fulham having actually had three shots on target to Arsenal's two. But the Cottagers have survived some perilous situations in their own box.
12.58pmBENCH WATCH: Emery will be fairly pleased with what he has seen in that first half, but Aubameyang is a pretty good weapon to have in reserve if the scores remain deadlocked past the hour. Jokanovic needs to change shape so Christie could be sacrificed for another midfielder.
1.00pmIn each of Arsenal's last five Premier League wins, they have been level at half time and gone on to win...
46 minKICKOFF: The action resumes with neither manager choosing to make a change at the break. It does look as though Jokanovic has stuck with the back three.
47 minIwobi should do a lot better to pick out Mkhitaryan who was in acres of space on the penalty spot but Le Marchand is well positioned to intercept.
48 minSAVE! Bettinelli makes an outstanding save to keep the scores level, diving at full stretch to push away a powerful Bellerin shot that was flying in, after Sessegnon's poor touch had teed up the Spaniard. That is the sort of save that has attracted Gareth Southgate's attention.
49 minGOAL!FULHAM 1-2 ARSENAL (ALEXANDRE LACAZETTE)
49 minBettinelli quickly turns from hero to villain as Arsenal regain their lead. That may be harsh on the Fulham goalkeeper, as Lacazette's 20-yard shot found the bottom corner, but you can tell from his reaction that he was disappointed not to keep it out after getting a hand to it. It caught him by surprise but it is another fine finish from Lacazette who is running into his Lyon-best form.
51 minArsenal have continued their sequence of scoring twice in every league game for the seventh time in a row. With Lacazette in this form and Aubameyang yet to hit his stride this season, there is no reason that can't continue.
53 minIf Arsenal go on to win this game, Lacazette will deservedly take the headlines but it is Torreira who is taking the acclaim of the visiting fans. The Uruguayan is exactly what the Gunners have been looking for - a midfielder who has the ability to play the Arsenal way but do the dirty stuff too.
55 minSUBSTITUTION: Jokanovic reacts to going behind by making a change, bringing on Aboubakar Kamara for Ream and finally dropping the back five. Kamara will go up top alongside Mitrovic and can be a handful.
57 minNot for the first time this afternoon, the Arsenal physio is on, this time to tend to Mustafi who landed awkwardly after getting up for a high ball. The German is clutching his knee but looks as though he is going to run it off.
59 minThe ball nearly drops to Lacazette in the Fulham box but Bettinelli is out before the Frenchman can pounce for his hat-trick.
61 minCHANCE! Wonderful opportunity for Fulham, who switch the play seamlessly to work a crossing opening for Christie. He drops it right onto the head of Kamara, or shoulder rather, as the substitute completely miscued his effort from close range. He was unmarked and should have done a lot better.
63 minSUBSTITUTIONS: A change apiece from either manager, with Kevin McDonald replacing Anguissa in the Fulham midfield and Aubameyang coming on for Welbeck, who played in midweek and was no longer affecting this game.
65 minReferee Paul Tierney is yet to show a yellow card this afternoon but may have been tempted there with Xhaka catching Seri with a high foot. The Arsenal skipper for the day gets away with one there.
66 minSUBSTITUTION: Aaron Ramsey has not got the phone call from his wife so is going to get the last 23 minutes here. Iwobi comes off so Mkhitaryan may be shifted out to the wing.
67 minWhat an immediate impact from Ramsey, who scores within 38 seconds of coming on! Not only that, but it is a goal of the season contender, a classic Arsenal move up the pitch full of one-touch passing and silky flicks, started by the Welshman in his own half and finished with a back-heel. Sublime stuff.
69 min"We've got our Arsenal back", sings the visiting section at Craven Cottage. That goal was up there with the great team goals of the Wenger era - wait until you see it on Match of the Day later. Wow. With his other half expecting twins, this is a weekend that Ramsey will not forget in a hurry!
71 minYELLOW CARD! We do now have our first booking of the game, awarded to Schurrle for a cynical foul on Torreira.
73 minFulham's defence is wide open now, and Mkhitaryan would have been clean through on goal had Sessegnon not blocked Aubameyang's attempt to switch the play to his old Borussia Dortmund pal.
75 minCHANCE! Mitrovic has been feeding off scraps today and gets half a chance here, being played onside from Kamara's flick-on but it was very difficult for him to generate any power on a header which Leno gathered at a snail's pace.
77 minAnother goal for Arsenal would see them leapfrog Tottenham in the table on goal difference. That should be all the motivation they need...
79 minGOAL!FULHAM 1-4 ARSENAL (PIERRE-EMERICK AUBAMEYANG)
79 minAubameyang gets in on the act, and it is another clinical finish from Arsenal this afternoon. Mkhitaryan spreads the play to Bellerin, who feeds the ball into the feet of Auba. Similarly to how Lacazette did earlier, he spins away from his defender and buries his shot into the bottom corner, a controlled volley his left foot. There is the fourth goal that will take Arsenal third in the table before Chelsea play Southampton.
81 minSUBSTITUTION: Lacazette has had a fine day but won't be taking the match ball home. Matteo Guendouzi, who has adapted well to Premier League life from Ligue 2, comes on for the final 10 minutes.
83 minArsenal are picking apart Fulham on every attack now and a better pass from Ramsey would have set Aubameyang up for a fifth.
85 minSUBSTITUTION: Vietto was lively in the first half but has seen nothing of the ball since the restart. Former Celtic midfielder Stefan Johansen replaces the on-loan forward in Fulham's last substitution.
87 minGuendouzi releases Bellerin down the right and the cross on the half-volley is fantastic, destined for Aubameyang's head eight yards from goal before Bettinelli dives to make a clearing punch.
89 minThis is another reality check for Fulham upon their return to the big time. They weren't expecting to take the Premier League by storm but there weren't many tipping them for relegation. That is a real possibility if they don't improve defensively.
90+1 minGOAL!FULHAM 1-5 ARSENAL (PIERRE-EMERICK AUBAMEYANG)
90+1 minThe Gunners are rampant as Aubameyang caps off the most impressive performance of Emery's reign to date with a stoppage-time fifth. Ramsey splits the defence with a clever outside-of-the-foot pass and the Gabonese striker was never going to miss one-on-one with Bettinelli. This is a drubbing now.
1.56pmThat is a major statement from Arsenal. Two goals apiece for Lacazette and Aubameyang, and a goal of the season contender from Ramsey contribute to the best performance and result of the Unai Emery reign to date. Could they play a role in the top-four picture this campaign? On today's evidence, definitely.
1.58pmThat is it from our coverage from Craven Cottage. You can read our match report on the action here, and stay tuned with Sports Mole throughout the afternoon for coverage from Southampton vs. Chelsea, and the big one - Liverpool vs. Manchester City from 3.30pm. Goodbye from me!