Norwich created enough chances to have won this game by half time, but a combination of poor finishing by the home side, and last ditch defending by the visitors, enabled Portsmouth to end City's unbeaten run of six games.
With leading striker Grant Holt serving a one-match ban, Paul Lambert chose to recall Simeon Jackson to partner Chris Martin up front, otherwise it was the same starting line-up that won away at Derby last week.
The Canaries kicked off attacking the Barclay end goal, but had to withstand some early pressure from Pompey before getting their game together. Liam Lawrence had John Ruddy diving across his goal with a free kick in the fourth minute, but the ball grazed the side netting.
Jackson should have opened the scoring in the eighteenth minute when put through by Chris Martin's deft header, but his weak shot was easily saved by Jamie Ashdown.
Two minutes later Jackson got his own head to a David Fox corner from the left, but the ball went the wrong side of the far post.
After thirty-three minutes Chris Martin's shot was saved and two minutes before the break his well placed header was deflected for a corner.
HALF-TIME: City 0 Pompey 0
The second half did not match the first as far as the home fans were concerned. Barnett was booked for a fairly innocuous challenge after fifty minutes; then Lawrence fired over after dispossessing Andrew Crofts; while at the other end Wes Hoolahan's shot went wide.
The turning point came after seventy-two minutes when David Nugent burst down the right wing, leaving Simon Lappin trailing in his wake, before driving in a low cross which David Kitson turned high into the net from close range.
Four minutes later Henri Lansbury had a shot saved and for the remainder of the game Norwich threw players forward, including all three substitutes, desperately searching for an equaliser. It looked as if their efforts would be rewarded when Elliott Ward's header beat the keeper, but Kitson proved his worth at both ends of the pitch with a headed clearance off the goal line.
The killer blow came deep into stoppage time when Leon Barnett found himself outnumbered two to one in defence. Nugent went down under his challenge and referee Simon Hooper had no hesitation in pointing to the penalty spot. He then appeared to show Barnett a second yellow card followed by a red.
Greg Halford blasted home the spot kick, but the 0-2 scoreline was very unfair on the home fans who had seen their team control eighty percent of the match with nothing to show for it.
To add insult to injury, the fans in the Barclay Stand had to endure obscene gestures made in their direction by Nugent when he should surely have confined himself to celebrating in front of the large contingent of his own fans who had every right to congratulate their players for scoring from the only two shots they had on target!
FULL-TIME: City 0 Pompey 2