Pompey 0 Fleetwood 1
Lady Luck was not smiling on Pompey as Fleetwood left the south coast with all three points.
The high-flying visitors did look impressive, but it took an unfortunate Sonny Bradley own-goal to secure three points.
The Blues did not create too many chances at the other end, although Simon Ferry was a constant menace for them.
Guy Whittingham made four changes from the side that won at Burton the previous week.
David Connolly returned from a three-match suspension, while Shaun Cooper, Bondz N’Gala and Marcos Painter started in a new-look defence.
Yassin Moutaouakil (suspended) and Joe Devera (hamstring) were both unavailable, while Jed Wallace and Danny East joined new loan signing John Marquis on the bench.
Fleetwood arrived at Fratton Park having won five of their opening seven matches in League Two.
And they almost took an early lead against Pompey, with John Sullivan just about managing to parry Jamille Matt’s effort against the post.
The hosts were then temporarily down to 10 men when a challenge left Johnny Ertl with a nasty cut to the face.
The bloodied Blues skipper was forced to return to the dressing room and get stitched up before being allowed to return to the pitch.
Pompey were offered a decent chance of their own on 12 minutes when Patrick Agyemang was cynically hacked down by Dean Howell just outside the box, but Ricky Holmes’ free-kick came to nothing.
Both sides were looking to pour forward at every opportunity, with the match being played at a breathless pace.
Ferry, in particular, looked impressive for the Blues, winning every ball in the middle of the park.
Despite the attacking intent, however, neither Sullivan nor his Fleetwood counterpart Scott Davies were being tested.
That was until 32 minutes when Pompey’s keeper got down quickly to keep out Antoni Sarcevic’s angled drive.
Junior Brown then wasted a good opportunity, volleying high over the bar after being left in space to meet Gareth Evans’ cross.
Fleetwood were desperately trying to take a lead into the interval and, just before the break, Sullivan had to fly to his left in order to push clear a curling Evans cross that evaded everyone as it flew towards goal.
Half Time: Pompey 0 Fleetwood 0
Pompey made a bright start to the second half, although it was the visitors who should have opened the scoring on 50 minutes.
Jeff Hughes’ cross managed to creep through towards the far post, but Evans’ seemed to be taken by surprise as the ball hit him and flew inches past the post.
Evans then fired narrowly wide before Sullivan had to push Sarcevic’s fierce drive over the crossbar as Fleetwood started to take control.
Ferry was still trying to drive Pompey forward, although it was a short corner routine that saw them go close on 62 minutes.
Holmes drilled the ball into the area, where Connolly arrived to meet it and fire in a shot that was bravely blocked.
But it was Fleetwood who broke the deadlock on 67 minutes – thanks to a large slice of fortune.
Firstly, Pompey were fuming that referee Graham Horwood failed to penalise Ryan Cresswell for what they thought was a foul on Agyemang in the build-up.
Matt then burst through on goal and although Sullivan did brilliantly to tear off his line and deny the striker, the ball ricocheted off Bradley and rolled over the line.
Whittingham soon made a change, with Ertl making way for Romain Padovani in the centre of midfield.
Wallace and Tom Craddock followed him onto the pitch moments later, as Andy Barcham and Agyemang were replaced.
But, despite plenty of endeavour, the Blues were unable to find an equaliser in the closing stages.
Pompey (4-4-2): Sullivan; Cooper, N’Gala, Bradley, Painter; Holmes, Ertl (c) (Padovani 72), Ferry, Barcham (Wallace 75); Agyemang (Craddock 79), Connolly
Booked: N’Gala, Holmes
Subs not used: Smith, Butler, East, Marquis
Fleetwood (4-3-2-1): Davies; McLaughlin, Pond, Cresswell (c), Howell; Sarcevic, Schumacher (Murdoch 90+3), Hughes; Brown, Evans (Hogan 87); Matt (Ball 68)
Goals: Bradley (og) 67
Booked: Cresswell, Matt
Subs not used: Lucas, Roberts, Blair, Parkin
Referee: Graham Horwood
Attendance: 15,809 (187 Fleetwood fans)