The winning goal arrived seven minutes from time as Marc Pugh bundled home a close-range effort to earn the Cherries a hard-earned triumph.
Read below to see how the action unfolded at Fratton Park.
Hello, and welcome to Sports Mole's live coverage of the match in the FA Cup fourth round between Portsmouth and Bournemouth.
In the 2009-2010 campaign, Portsmouth were trying to secure survival in the Premier League and Bournemouth were looking to secure promotion from League Two. Just six years later, the two teams have switched position in the English football pyramid ahead of what promises to be an exciting FA Cup fixture between two clubs based on the South Coast.
The odds point in favour of a Bournemouth win and justifiably so. Eddie Howe's men have impressed over the past couple of months and make the 52-mile trip to Fratton Park sitting four points above safety in the Premier League table. That said, Pompey have performed consistently since the start of August and they are likely to relish their tag of underdog heading into this match.
Without further ado, let's take a look at the two starting lineups.
PORTSMOUTH XI: Fulton; Davies, Burgess, Clarke, Stevens; Close, Doyle (c); Roberts, McNulty, Bennett; McGurk
PORTSMOUTH SUBSTITUTES: Jones, Webster, Barton, Evans, Tollitt, Naismith, Chaplin
BOURNEMOUTH XI: Federici, Smith, Elphick, Distin, Cargill, O'Kane, McDonald, Iturbe, King, Grabban, Murray
BOURNEMOUTH SUBSTITUTES: Allsop, Francis, Simpson, Butcher, Pugh, Wakefield, Ritchie
After seeing his side lose at home to Oxford United in midweek, Portsmouth boss Paul Cook has opted to make a number of changes to his team for today's contest. Adam McGurk has been included in attack, while Christian Burgess and Ben Close have also been handed starts.
As for Bournemouth, manager Eddie Howe has opted to make 10 alterations to his starting lineup. Defender Adam Smith is the only player to keep his spot in the side as the likes of Sylvain Distin, Juan Iturbe and Lewis Grabban are preferred.
The FA Cup action has already gotten underway this afternoon and it appears that Tottenham Hotspur are well on their way to the last 16. They hold a 2-0 lead over Colchester United, with Nacer Chadli and Eric Dier netting the goals. Keep up-to-date with the closing stages of that match here.
HEAD TO HEAD! Today's match will represent the 21st time that the two clubs have met, with Portsmouth holding a slender 9-7 advantage, with the other four occasions ending in stalemate. However, it is Bournemouth who have prevailed in the last two matches, but both fixtures in 2013 were played at Dean Court, in League One and the League Cup respectively.
The eagle-eyed among you would have noticed that Matt Ritchie has been named on the Bournemouth bench this afternoon. In normal circumstances, he would perhaps have been given the afternoon off like many of his teammates, but the 26-year-old probably insisted that he be named in the squad having started his career at Portsmouth. Ritchie played 10 times for Pompey before fially making the permanent switch to Swindon Town after two loan spells.
The goals are still flying in at Colchester. Spurs looked to have sealed victory with a third goal, but the hosts have reduced the deficit. Catch the final 10 minutes plus added-on time here.
Back to this game and let's take a look at the job that Paul Cook has done since he moved to Fratton Park in the summer. Some questioned his decision to drop down a division after three years at Chesterfield, but so far, it looks a great switch for the 48-year-old. He won't be content with the playoff position that they currently occupy in League Two, but after the club ended the last campaign in 16th place, he has made huge improvements in just over half-a-year in charge.
His opposite number Eddie Howe made a similar move back in 2012. Howe departed Burnley to drop down to League One with a club he had previously managed, but over the course of three years, he has transformed a club who were playoff contenders in the third tier of English football to a team who look comfortable in the top flight. Such success has seen Howe be linked with several top jobs, but the 38-year-old is fully committed to continue to establish Bournemouth in the Premier League. If they can retain their status this season, who knows - maybe they can replicate Portsmouth's achievements under Harry Redknapp.
If you would prefer to keep up-to-date with all the FA Cup matches in one place, don't worry, you can do so by clicking here. You will be able to take a look at all of the team news ahead of the 11 3pm kickoffs, and as usual with cup competitions nowadays, there are changes aplenty.
RESULT! The full-time whistle has gone at Colchester and it's an emphatic win for Spurs, who have eased to a 4-1 triumph against their League One opponents. Want to read about what happened at the Colchester Community Stadium? You can do so right here.
He has spent much of the season on the sidelines with an ankle injury, but for the first time since September 12, Tommy Elphick takes his place in the Bournemouth team.
PREDICTION! Portsmouth have already showed this season that they are capable of beating teams from leagues above them at Fratton Park - Derby County and Ipswich Town found that out first-hand. However, despite the mass changes, this is an opportunity for Bournemouth's squad players to stake a claim for a first-team spot and while we expect it to be close, we think that the Cherries will run out 2-1 victors.
Before the two teams come out, a quick stat to throw in your direction. Bournemouth have not made the fifth round since 1989, while this is the first time Portsmouth have made the fourth round since they reached the final in 2010. Something has got to give!
Here comes the two sides to a warm reception from both sets of supporters. The home faithful are going to be well behind their team this afternoon but there appears to be a large contingent from Bournemouth too. This has all the makings of a terrific cup tie.
We are underway at Fratton Park.
Bournemouth win the first free kick of the match after a foul on Murray, but the resulting delivery from O;Kane was headed clear. Decent start from Bournemouth, who will be wanting to stamp their authority on this match.
The first sight of goal for Pompey comes through McNulty, who did well to charge into the penalty area under pressure from Bournemouth defenders, but Distin was eventually able to get the ball away.
McNulty, who has scored seven goals in 14 games since moving on loan from Sheffield United, gets into another threatening position before shooting wide. However, he was correctly adjudged to have been offside. Promising from the Scot, though.
You have to say that Portsmouth have settled the better of the two teams. Not much from the likes of Iturbe or Grabban - who have recently transferred to Bournemouth from Roma and Norwich City respectively.
Better from Iturbe, who wins a free kick for his side before winning a header to set up Murray, but his strike partner's effort is tame and easily dealt with.
We spoke about Portsmouth's home record earlier, but they have drew half of their Fratton Park fixtures in League Two. It wouldn't be the biggest surprise if the same result occurs here. Not many chances to speak of so far.
Right on the quarter-hour mark, Pompey win a corner with Davies's set piece causing plenty of confusion in the penalty area. The ball bounced up and appeared to strike a Bournemouth player close to his arm, but the referee quickly said no.
Slowly but surely, Portsmouth are beginning to build up a head of steam. A couple of corners are won in quick succession without any opportunities being created but it is keeping Bournemouth on the back foot. I'm sure that Eddie Howe would have expected a little better from his team given that they sit 58 places above their hosts in the English league pyramid.
BOOKING! The first caution of the day goes to Portsmouth's Burgess, who went in late on Murray. The referee could perhaps have been a bit more lenient but the Pompey defender can have no complaints.
CHANCE! O'Kane whips in another set piece and it's Murray who gets on the end of it. However, he cannot direct his header on target, with the ball drifting just wide of the post.
That effort has seen Bournemouth get back into the game but they are still trailing in the possession stats. Portsmouth have had 54% of the ball so far as we head into the final 20 minutes of the first half.
SAVE! Bournemouth are starting to gain some sort of control on this tie now. Six minutes after Murray sent a header wide, Portsmouth goalkeeper Fulton is forced into an excellent stop to deny Iturbe, with the Argentine's effort being turned onto the post. The Cherries are knocking on the door.
There are a few goals starting to go in elsewhere. Remember, you can follow all of the 11 FA Cup fixtures here.
He haven't mentioned Distin making his return to Fratton Park - apologies, Sylvain! The 38-year-old won the FA Cup with Portsmouth in 2008, but he's doing a fairly good job of nullifying any threat from his former club so far. He has also missed a headed chance at the other end of the pitch too.
Chances and goalmouth action have dried up over the past 10 minutes. Bournemouth are having the better of general play but Portsmouth are doing a solid job of staying on level terms. You wouldn't believe that three divisions separated these teams if you didn't already know.
Portsmouth look happy to try to see this out until the break. While Bournemouth maintain their threat on the counter, Pompey have still had a lot of the ball, as much as 56% of the possession over the first 42 minutes.
GOAL! Portsmouth 1-0 Bournemouth (Gary Roberts)
Well this was not in the Bournemouth script! After a period of possession, Portsmouth take the lead through Gary Roberts, who slid in to convert a pass from Marc McNulty for his seventh goal of the season. Fratton Park is rocking!
There will be one minute of added-on time.
HALF TIME: Portsmouth 1-0 Bournemouth
The half-time whistle goes on the South Coast and it's the underdogs who lead! Bournemouth probably don't deserve to be behind based on the general run of play, but Gary Roberts's goal separates the two sides. Are we on our way to a big cup upset?
The two teams are slowly starting to emerge for the second half. Portsmouth will certainly be feeling confident about this match now. Bournemouth's bench does not contain too many options either. This should be an interesting 45 minutes.
Bournemouth get the action back underway.
Not much to report from the opening exchanges of the second half. Portsmouth conceded a couple of free kicks in the Bournemouth half but nothing came from either.
Portsmouth feel as though they have a strong case for a penalty but Mike Dean feels that Stevens was dispossessed fairly inside the 18-yard box. Hard to see what the right decision was without a second glance.
SHOT! After a foul by O'Kane around 35 yards from goal, Portsmouth have the chance to apply some more pressure, but Davies, rather ambitiously, decides to shoot. It's a good effort but Federici comfortably made the save.
CHANCE! Portsmouth are pushing for a second here - the expected Bournemouth response has not materialised. Bennett played a neat ball through to Roberts but the goalscorer from the first half found the angle too tight and dragged his effort wide. Howe won't likely what he is seeing at the moment.
Howe must be contemplating changes but who does he take off and who does he throw on? Only Ritchie, Pugh and Francis stand out as possible introductions.
SUBSTITUTION! The changes were inevitable. Howe opts to throw on both Ritchie and Pugh, with Murray and Iturbe being replaced. Not a good sign for the on-loan Roma attacker...
SUBSTITUTION! Portsmouth boss Cook has also made two alterations. Evans and Webster take the place of Roberts and Burgess.
CHANCE! Ritchie got a warm reception from the Pompey fans upon his arrival into the game but they may have changed their tune had the Scot's pass to Grabban resulted in a goal, rather than the striker drilling his effort high over the crossbar.
Like they did at the midway point of the first half, Bournemouth are starting to enjoy more of the play, but with a lead to defend, Portsmouth look determined to hold firm. This could be a long 22 minutes for the hosts.
GOAL! Portsmouth 1-1 Bournemouth (Joshua King)
The closing stages are going to feel that much longer for Portsmouth. After a free kick is given away wide on the left flank, O'Kane's delivery found the head of King, who made no mistake from close range. Bournemouth are favourites now.
To their credit, Portsmouth have not decided to sit back. Bennett forced a save out of Federici from a free kick soon after the equaliser, but it was no problem for the Australian goalkeeper. A quarter-of-an-hour remaining at Fratton Park.
Both sides have now made all of their allotted substitutions, so if there is going to be a winner, it will come from one of the 22 players already on the pitch. I think this is going to end in a stalemate but I have been proven wrong in the past.
CHANCE! Big chance for Bournemouth. Grabban is found in plenty of space inside the penalty area, but he takes too much time and Clarke is on hand to get a superb challenge in on the forward.
GOAL! Portsmouth 1-2 Bournemouth (Marc Pugh)
Told you I sometimes (not always) get proven wrong. Fulton is really unlucky having produced an excellent stop to deny Grabban but Pugh is in the right place at the right time to convert the rebound. That's harsh on Pompey but they have seven minutes plus added-on time to redeem themselves.
Portsmouth are desperately searching for an equaliser but I don't think that they have a whole lot left. They have put so much energy into this performance and it looks like they will go without reward.
There will be four minutes of added-on time. Can Portsmouth make one last push?
Portsmouth win a free kick and Fulton needs no second invitation to make his way up the field. It all comes to nothing, though, and that could be that.
FULL TIME: Portsmouth 1-2 Bournemouth
The full-time whistle goes at Fratton Park and a late comeback from Bournemouth has earned the Premier League side a place in the FA Cup fifth round. Portsmouth can be proud of their performance but the extra quality of their opponents eventually proved to be the difference.
That will be all from Sports Mole for this match, but we hope that you can stick around for all of the results and reaction from elsewhere. Goodbye for now.