Utaka scored Portsmouth's first goal and set up their second and third
Sunderland remain in serious danger of relegation after relinquishing a one-goal lead to lose at Portsmouth.
The visitors took the lead against the run of play when Calum Davenport's cross was tapped in by Kenwyne Jones.
John Utaka fired in an equaliser a minute later and then forced Phil Bardsley to bundle in an own goal that gave the home side the lead.
Sunderland's misery was sealed late on when Utaka found substitute Armand Traore and he fired in an angled shot.
Having earned their first point in eight matches at Bolton last week, Sunderland kept the same side, with top scorer Djibril Cisse on the bench, and their initial priority was to avoid defeat as opposed to chasing victory.
In contrast, Portsmouth brought in Kanu and Utaka to form a three-man front line with Peter Crouch as they looked to celebrate Premier League safety with a flourish.
Sbragia rues missed chances
Such progressive thinking almost paid an instant dividend when Crouch headed the ball against the post and then saw it dribble tantalisingly along the unprotected goal-line before a desperate, outstretched foot from Anton Ferdinand poked it clear.
Sunderland's attacking deficiency was apparent from their first attack as Grant Leadbitter, Dean Whitehead and Steed Malbranque all had efforts at goal but none were struck cleanly enough to trouble Portsmouth keeper Asmir Begovic, who was in for the injured David James.
Kieran Richardson was guilty of missing a host of good chances at Bolton and again wasted a decent opening here after half an hour, collecting a cute back-heel from Jones on the edge of the box but blazing his effort over the bar.
Ten minutes later, Jones replicated Crouch's earlier effort when he headed Malbranque's cross against a post and lay helpless as the ball ran along the goal-line and, ultimately, to safety.
Two half-time substitutions - Traore and Younes Kaboul for Richard Hughes and Kanu - liberated Portsmouth, who made all the running early in the second half.
However, after fending off the home side for nearly 20 minutes Sunderland scored with their first attack.
Centre-back Davenport got free down the right before swinging over a precision deep cross that beat Sol Campbell and found Jones who tapped in first time at the far post. The visitors were barely able to consider the relegation-avoiding implications of the goal before Pompey turned the game on its head and brought the Black Cats fears flooding back.
Firstly, a long ball forward for Portsmouth was headed clear but struck Grant Leadbitter and ricocheted into the path of Utaka in the box, the striker holding off the challenge of Davenport and firing past Fulop.
Then, eight minutes later, a long punt forward by Begovic resulted in a woeful attempted clearance from Ferdinand as he swung at and missed the ball. His error allowed Utaka to run clear, round Marton Fulop and force Bardsley into a sliding challenge that bundled the ball into his own net.
Hart delighted to seal survival
Now desperately chasing the game, Sunderland introduced Cisse along with fellow striker Daryl Murphy from the bench and the former was inches away from producing an instant reward with a shot that flew wide.
Jones again was guilty of wasting a good chance moments later when he found space at the far post but could only head straight at Begovic.
It was to prove extremely costly as Portsmouth immediately went down the other end to score; Utaka finding Traore on the left and the defender drilled a shot past Fulop into the far corner to seal the win.
The result leaves Sunderland needing a win against Chelsea at Stamford Bridge on Sunday to guarantee their safety.
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