The visitors were reduced to 10 men after half an hour, when Aurelien Joachim was dismissed for a foul on Andre Almeida.
Read how all the action unfolded below:
5.32pmGood evening! It's less than half an hour until Portugal begin their final qualifier for next summer's World Cup against Luxembourg, knowing that they're likely to be heading into the playoffs. Let's take a look at the team news.
5.34pmPORTUGAL STARTING XI: Patricio, Almeida, Neto, Costa, Coentrao, Veloso, Moutinho, Josue, Nani, Varela, Postiga
5.37pmWe're still waiting for Luxembourg's team news, but the obvious absentee from the Portugal starting lineup is Cristiano Ronaldo. The home side know that they would have to trounce the visitors and hope for Russia to lose heavily to Azerbaijan in order to top the group, so have decided to rest their superstar captain. However, with the likes of Nani and Joao Moutinho in the starting lineup, it's still a strong side for the hosts.
5.40pmLet's take a quick look back at the two sides' qualifying campaigns so far. Portugal started well, winning their opening two games, but went three match without a victory, before returning to form during the summer. Meanwhile, Luxembourg claimed just three points from their opening seven games of the qualifiers, before securing their only victory so far, a 3-2 win over Northern Ireland. Should Northern Ireland lose tonight, a draw or better would be enough for Luxembourg to avoid finishing bottom in group F.
5.43pmLUXEMBOURG STARTING XI: Joubert, Janisch, Philipps, Mutsch, Jans, Gerson, Payal, Bensi, Joachim, Laterza, Da Mota
5.45pmPORTUGAL SUBSTITUTES: Lopes, Beto, Sereno, Rolando, Antunes, Martins, Bruma, Micael, Custodio, Almeida, Pizzi, Eder
5.48pmLUXEMBOURG SUBSTITUTES: Oberweis, Hoffman, Malget, Martino, Peters, Bastos, May, Luisi
5.51pmAll but four of the Luxembourg squad play their club football in their home country. Mario Mutsch should be used to playing on the big stage though, as he recently travelled with Swiss side St Gallen for their Europa League tie against Swansea at the Liberty Stadium.
5.53pmThe players are just about to make their way out ready for this evening's game.
5.56pmPREDICTION! While the anthems take place, it's time for a quick prediction. Realistically, this should be a comfortable evening's work for Portugal. I can see them winning this 4-0.
5.58pmWith the pre-match formalities out of the way, the team's are getting themselves into position, ready to get this match underway.
1 minPortugal get the game underway.
3 minThe home side are on the attack straight away, but Philipps manages to block Nani's run at the Luxembourg defence. Moutinho guides the team back in, but Joubert is able to collect his cross before Varela can get his head to the ball.
6 minCHANCE! Portugal win a free kick in a dangerous area when Payal hacks down Josue just outside the penalty area. Nani and Moutinho both line it up, and it's the Monaco player that takes it, but his effort creeps just wide.
8 minLuxembourg have hardly had a touch so far, this could be a long night for the visitors at this rate! Josue and Postiga look to play their way through midfield, but another wild challenge gives the hosts a free kick. Luxembourg have pretty much their entire team behind the ball as they desperately defend.
9 minPostiga is almost handed a golden opportunity to give his team the lead, as he finds himself in space in the penalty area as Moutinho loops the ball in, but his first touch is poor, allowing Joubert to rush out and dive on top of the ball.
10 minCHANCE! From a throw in, the ball falls to Nani, who tries to smash it in on the half-volley, but Joubert superbly gets a hand to it to keep it out of the Luxembourg net. It feels like it's only a matter of time before Portugal take the lead though.
14 minOFF THE BAR! Portugal immediately up the pace and it almost pays dividends, as Coentrao goes for a header from point-blank range. He has Joubert well beaten, but his effort is kept out by the crossbar. Meanwhile, there could be an injury concern for the visitors, as Laterza is down clutching his hamstring.
17 minNani makes a brilliant run down the right sideline and crosses in for Postiga, but the striker can't stretch his leg far forward enough, and the cross goes out the other side.
20 minNani is really controlling the play in midfield at the moment. He wins the ball from Payal before passing to Moutinho, who picks out Andre Almeida sprinting into the box, but Mutsch just manages to block the danger. Luxembourg go on the counter again, but Joachim gets caught offside on the edge of the penalty area.
23 minCHANCE! Moutinho is floored by a heavy challenge from Philipps to the right of the box. After a moment or two he looks ok though, and delivers a superb free kick to the head of Nani, who forces a lightening quick reaction from Joubert in the Luxembourg goal.
26 minJoachim makes a superb run through midfield before sending in a cross for the visitors, but he has no teammates there in support, allowing Costa to carefully nod the ball back to Patricio, who has had little to do in the opening 25 minutes of this match.
28 minRED CARD! Aurelien Joachim is shown a straight red for a studs-up tackle on Andre Almeida, leaving the Portugal midfielder in some pain, grabbing his shin, which took the brunt of the impact. It really was an ugly challenge from the Luxembourg forward.
30 minGOAL! Portugal 1-0 Luxembourg (Varela)
30 minMoutinho wastes no time exploiting the gap left by Joachim's departure, running at the back four before slotting the ball forward for Silvestre Varela. The striker holds onto the ball long enough to draw Joubert off the goal line before rounding the keeper to tap in to an open goal.
33 minIn more good news for Portugal, Almeida has been able to return to the pitch after receiving some treatment on the sidelines following a nasty tackle from Joachim. With the visitors down the 10 men and Portugal fully in control, this could become a bit of a rout.
35 minPayal earns himself a talking to from the referee for a clumsy tackle on Coentrao. The visitors need to watch their discipline, having already seen one player sent off. Portugal try to attack from the resulting free kick, but it's a comfortable take for Joubert.
36 minGOAL! Portugal 2-0 Luxembourg (Nani)
36 minMoutinho has the ball deep in the penalty area but his path to goal is blocked, so he pulls it back with an inspired back heel, which drops to Nani, who volleys it past Joubert to double the home sides lead. Nani and Moutinho have been a devastating combination so far this half!
39 minPortugal are showing no signs of taking their foot off the gas against the 10 men of Luxembourg, as Almeida, who is showing no signs of Joachim's earlier tackle, dashes down the sideline before looking to get a cross in, but Mutsch and Philipps are both waiting for the ball and manage to clear.
41 minBOOKING! Chris Philipps is shown the first yellow card of the match for a clipping the ankles of Nani, who was about to sprint into the box. It gives Portugal a free kick from a strong position.
42 minCHANCE! Josue takes the free kick and manages to beat the wall, but can't catch out Joubert, who has had a good half in goal for Luxembourg, despite his team's two-goal deficit.
44 minDISALLOWED GOAL! Coentrao thinks he's made it three, as Moutinho chips the ball forward for the defender, who smashes it in with a superb finish, before turning to see the assistant referee raise the flag for offside.
45+1 minCHANCE! Luxembourg win a free kick as Neto grabs hold of Bensi around 25 yards out. The midfielder takes the free kick himself and drills it hard and low, but Patricio just manages to hold on to it. That should be the last action of the half.
45+1 minHALF TIME: Portugal 2-0 Luxembourg
6.50pmSo Portugal are well and truly in control of this match at half time. Goals from Nani and Varela leave them 2-0 up against 10-man Luxembourg. Although not on the scoresheet. Joao Moutinho deserves a lot of credit for the home sides advantage, having set up both goals, and almost created a third for Coentrao just before the break.
6.52pmStefano Bensi's impressive free kick late in the first half will give the visitors hope. It was the first time that they had been able to test Rui Patricio, and he only just managed to make the save.
6.55pmWithout a doubt, the turning point of the half was the sending off of Aurelien Joachim. Luxembourg had been just managing to hold on until then, but the loss of the attacking midfielder left a big hole, giving Moutinho even more space in final third.
6.58pmLet's take a glance at a few stats from the first half. Unsurprisingly, Portugal saw the majority of the possession, with 70%. The hosts had 11 shots, with seven on target, compared to three efforts for Luxembourg, and just the one on target. Portugal committed just three fouls and picked up no cards, compared to the 12 fouls, one booking and one sending off for the visitors.
7.01pmAlthough a big win would keep Portugal in contention to top the group, they'll need a favour from Azerbaijan, who are losing 1-0 to group leaders Russia.
46 minLuxembourg kick off the second half.
46 minSUB! Luxembourg have made a change, bringing on striker Antonio Luisi in place of Stefano Bensi, who has had the visitors' only effort on target so far tonight.
48 minPortugal have continued from where they left off in the first half, dominating possession and looking to get forward whenever possible. Nani makes a couple of speedy runs, but can't find his way into the box.
49 minCHANCES! Joubert has to keep out a couple of quick-fire effort as Postiga takes the ball in for the home side, but strikes the ball straight at the visiting keeper, before Nani sees his follow up blocked.
50 minCHANCE! How are Luxembourg keeping the goals out at the moment?! Varela shows his pace before crossing for Nani, but the Manchester United man can't quite reach the ball.
50 minBOOKING! Josue is the first Portugal player to be shown a yellow card for a foul during the build up to the Varela cross.
53 minPortugal have barely left the Luxembourg penalty area in the last five minutes, but somehow Joubert is managing to stop the hosts from extending their lead. Nani almost manages to add his second of the night, but Postiga is caught offside before he manages to get his shot away.
55 minNani is in yet again, but manages to lose the ball on the edge of the box. Moutinho looks to send it back in, but some solid defending from Payal and Janisch manages to end Portugal's move, and they clear as far as the home side's back four to give themselves a rest.
58 minAntonio Luigi tries to get himself into the game for the first time, as the visitors look to run at the Portugal defence, but Costa quickly wins the ball back for the hosts, who immediately press down the other end.
58 minSUB! Miguel Veloso makes way for Hugo Almeida as the home side make their first change. A second may follow shortly, as Costa is limping towards the sidelines.
59 minSUB! Costa does indeed have to head off, having appeared to pick up a foot injury in the home side's latest attacking move. Henrique Sereno takes his place.
61 minMoutinho blasts forward a superb long ball which was perfectly weighted for Hugo Almeida, but the striker just edged offside. Portugal haven't tried the long ball much tonight, but as they're comfortably in control here they might as well try something a bit different.
62 minSUB! Rene Peters replaces Ben Payal for the visitors.
64 minBOOKING! Fabio Coentrao is shown a yellow card for a collision with Laterza.
65 minCHANCE! Luxembourg manage to apply some pressure in the Portugal box, as Gerson chips it forward for Mutsch, who tries to get the shot away, but loses out when challenged by Coentrao.
68 minLuxembourg are really starting to find their feet in this match. Laterza shows superb pace to break from midfield, but just loses his balance as he unleashes a shot from the edge of the area, forcing his finish well wide.
70 minBOOKING! Lars Gerson picks up a booking for a challenge on Postiga, which leaves the Portugal striker limping.
72 minCHANCE! Josue puts the ball in for Coentrao, whose finish is deflected wide for a corner. Nani manages to win the ball, but heads onto the crossbar.
74 minLuxembourg win a free kick around 30 yards from the Portugal goal, but Patricio watches Luisi's delivery all the way, making an easy save.
75 minCHANCE! Nani immediately goes on the counter for the home side, sending in an excellent cross, which Hugo Almeida tries to nod in for Portugal's third, but he comes up just short.
76 minSUB! Portugal make their final change, bringing on Vitorino Antunes in place of Fabio Coentrao.
77 minCHANCE! Antunes almost has an immediate impact, striking the ball from 40 yards out, forcing Joubert to push it wide for a corner.
78 minGOAL! Portugal 3-0 Luxembourg (Postiga)
78 minNani's corner is initially cleared, but Helder Postiga brings it back into to box before unleashing a powerful finish to all but secure the win.
81 minBOOKING! Da Mota is shown a yellow card for dissent.
82 minSUB! Luxembourg make the final change, taking off Da Mota for Massimo Martino.
85 minCHANCE! Hugo Almeida misses a superb chance to make it four, heading a Nani delivery inches high of the bar. Portugal aren't sitting back despite their comfortable lead.
88 minPostiga almost increases the home side's lead, but creeps offside, so the referee pulls the play back to the edge of the box for a foul on Nani earlier in the move. However, the Manchester United man smashes his free kick well high.
90+1 minPortugal continue to press as they head into two minutes of stoppage time, as Josue and Almeida link up in midfield before picking out Nani just inside the box, but Joubert makes another good save for the visitors. Nani and Moutinho really have been impressive tonight.
90+2 minFULL TIME: Portugal 3-0 Luxembourg
7.52pm3-0 possibly doesn't do Portugal's performance against 10-man Luxembourg justice, the visitors barely had a shot all match, while the home side peppered their opponents goal throughout.
7.55pmDespite the result, Portugal will have to go through a playoff if they're to reach next summer's tournament, as Russia drew with Azerbaijan, ensuring that they finish at the top of the group.
7.58pmThat's all from this match, but stick around for live coverage of the 8pm kickoffs, including commentaries of all of the British sides. Thanks for joining me this evening, goodbye.