Blues undone by league leaders
Pompey’s poor form continued with defeat to table-topping Rochdale at Spotland.
The visitors actually started brightly and both Toumani Diagouraga and Bondz N’Gala had opportunities to score.
But it all went downhill for the Blues once Matt Lund had given Dale a 15th-minute lead.
Pompey held out until half-time, but Ian Henderson and Peter Vincenti both struck after the interval to put the result beyond doubt.
Richie Barker made four changes to the side beaten by York at the weekend.
Patrick Agyemang returned to lead the line up front, while there were also starts for Wes Fogden, Ricky Holmes and Joe Devera.
Ryan Taylor, Jake Jervis and Rhys McCabe all dropped to the bench and Ben Chorley began a four-match suspension.
Pompey were on the attack straight from kick-off and a corner provided a scoring opportunity in the opening seconds.
The ball was only cleared as far as the edge of the box and Josh Lillis did well to keep out stand-in skipper Diagouraga’s shot as it flew through a sea of bodies.
But the hosts went straight down the other end and almost broke the deadlock themselves, as Jamie Allen sent a glancing header inches past the post.
Both teams looked capable of taking the lead and it was the Blues who were next to go close, with N’Gala’s header hacked of the line.
The ball came back into the box towards Devera, but the defender was unable to find the target with his effort.
It was Rochdale who did open the scoring on 15 minutes, however, as Lund headed home from close range after Pompey had failed to deal with a corner.
The visitors tried to hit back immediately and Lillis stayed alert to keep out Holmes’ drive from the edge of the box.
But Dale were still looking dangerous and a poor first touch saw a chance go begging for Henderson before Lund’s low shot was parried to safety by Trevor Carson.
Pompey saw out the rest of the half without too many problems, although they were unable to create any meaningful openings at the other end.
Half Time: Rochdale 1 Pompey 0
Jed Wallace fired a free-kick into the wall just after the restart, but it was the league leaders who looked more threatening at the start of the second half.
George Donnelly shot into the side netting following a quick break before Lund headed narrowly wide from Joe Rafferty’s cross.
And the hosts did double their advantage on 59 minutes as Henderson latched onto a long punt forward and Carson could only help his shot into the bottom corner.
The Blues soon had an opportunity to reduce the deficit, but Agyemang diverted his header straight into Lillis’ arms.
Things soon got even worse for Pompey as Vincenti converted Matt Done’s cross to give the hosts a three-goal cushion.
Barker quickly made his first substitution and it was an attaking one, with Devera making way for Taylor.
It failed to have much of an impact, however, as the Blues struggled to keep possession inside their opponent’s half.
And Jack Whatmough had to get a last-gasp touch on Donnelly’s cross to stop Vincenti from adding a fourth on 77 minutes.
But that was not much consolation for the travelling Pompey fans who saw their side suffer a third successive defeat.
Rochdale (4-1-4-1): Lillis; Rafferty, Bennett, Lancashire (c), Done; Rose; Vincenti (Bunney 90), Lund, Allen, Henderson; Donnelly (Cummins 78)
Goals: Lund 15, Henderson 59, Vincenti 62
Subs not used: Thomson, Kennedy, Tanser, Hery, Porter
Pompey (4-2-3-1): Carson; Alfei, N’Gala, Devera (Taylor 65), Shorey; Diagouraga (c), Whatmough; Fogden, Wallace, Holmes; Agyemang
Subs not used: Smith, Bradley, Ertl, McCabe, Drennan, Jervis
Referee: Nigel Miller
Attendance: 2,746 (471 Pompey fans)