Wallace goal the highlight
A sensational strike from Jed Wallace could not prevent Pompey from sliding to defeat at Fleetwood.
The midfielder came off the bench to net an impressive solo effort, but it proved merely a consolation.
Jon Parkin had earlier put the Cod Army ahead before a controversial penalty decision gave Antoni Sarcevic the opportunity to strengthen their advantage before the break.
Jamille Matt added a third after the interval and Wallace’s contribution could not spark an unlikely comeback.
Richie Barker made four changes to the side held by Burton during the week.
Jack Whatmough and Daniel Alfei came in for the injured duo of Romain Padovani (calf) and Ben Chorley (Achilles).
There was also a new pairing up front as Ryan Taylor and Patrick Agyemang made way for Jake Jervis and Michael Drennan.
The hosts started brightly, with half chances for both Sarcevic and Steven Schumacher in the opening stages.
But Pompey improved as the half progressed, testing Fleetwood’s defence with a couple of quick passing moves.
That good work was undone when the Cod Army broke the deadlock after 16 minutes, however.
Matt was first to reach a cross from the right and although his shot was superbly saved by Trevor Carson, the loose ball was bundled home by Parkin.
Pompey responded well to falling behind and Drennan’s trickery twice forced Fleetwood into some desperate blocks.
But they still fell further behind on 26 minutes, although the Blues were fuming that a penalty was awarded for Alfei’s challenge on Josh Morris.
Referee Iain Williamson was not going to change his mind, however, and Sarcevic stepped up to confidently slam home the spot-kick.
Pompey tried to reduce the deficit before the break, but struggled to find any fluidity going forward.
They finally clicked on 41 minutes and it took a fine block from Conor McLaughlin to deny Jervis after Alfei and Wes Fogden had combined well down the right.
Half Time: Fleetwood 2 Pompey 0
Pompey had lots of early possession at the start of the second half, but were still unable to test Chris Maxwell in the Fleetwood goal.
The hosts did create an opening, though, and Carson had to be at his best to deny Charlie Taylor, while Matt was unable to convert the loose ball.
But Matt did increase their advantage on 56 minutes, poking home from close range following an almighty goalmouth scramble.
Wallace was immediately brought on to replace Fogden and could not quite beat Maxwell to a long pass seconds later.
But he did pull one back with a fine solo effort on 63 minutes, beating several players before lashing home an unstoppable shot from the edge of the box.
Agyemang was soon off the bench as Nicky Shorey made way in an attacking switch, with the Blues looking to build some momentum.
But it was Joe Devera who almost reduced the deficit further, as his header was palmed over the bar by Maxwell.
Pompey kept pushing forward in search of a second goal that would set up a thrilling finale, but they were unable to breach the Fleetwood defence again.
Fleetwood (4-1-3-2): Maxwell; McLaughlin, Pond, Roberts (c), Taylor; Murdoch; Sarcevic (Blair 84), Schumacher (Goodall 71), Morris; Matt, Parkin (Mandron 81)
Goals: Parkin 16, Sarcevic 26 (pen), Matt 56
Booked: Schumacher, McLaughlin
Subs not used: Davies, Hughes, Jordan, Evans
Pompey (4-4-2): Carson; Alfei, N’Gala, Devera, Shorey (Agyemang 64); Fogden (Wallace 58), Diagouraga (c), Whatmough, Holmes; Jervis, Drennan (Taylor 78)
Goals: Wallace 63
Subs not used: Smith, Bradley, Painter, Racon
Referee: Iain Williamson
Attendance: 3,509 (855 Pompey fans)