A Jermain Defoe double helped Portsmouth to a 4-2 win over Alex McLeish's relegation-threatened Birmingham.
Jermain strikes at the double to sink battling Birmingham
A Jermain Defoe double helped Portsmouth to a 4-2 win over Birmingham City who remain in trouble at the foot of the Premier League.
Defoe struck twice in the opening nine minutes - the first from the penalty spot - to give Harry Redknapp's men the dream start.
But plucky Birmingham struck back immediately through Fabrice Muamba and levelled before half-time thanks to a fabulous free-kick from Sebastian Larsson.
Pompey got their noses back in front when Hermann Hreidarsson bundled the ball home from close range but the visitors continued to press in search of an equaliser.
Both managers made changes in the closing stages but with Blues pushing forward as time ticked away, Pedro Mendes found substitute Kanu unmarked five yards out and he headed home to seal victory for the FA Cup semi-finalists.
Defoe, who could suffer the heartache of missing two Wembley finals having played for Tottenham in both the Carling Cup and the FA Cup before joining Pompey, appeared to have won the game for his new team with two goals inside the first eight minutes.
He opened the scoring from the penalty spot in the sixth minute, confidently converting after defender David Murphy handled a cross by Milan Baros.
Powerless
Two minutes later he notched a typical poacher's goal, his fifth for the club and 12th this season.
Maik Taylor could only palm away a long shot by Sulley Muntari and then repeat the feat with Baros' follow-up - but he was powerless to prevent Defoe sliding in to bury the loose ball.
But battling Birmingham - who left new £5million striker James McFadden on the substitutes' bench - came bouncing back to level matters before the break with former Arsenal pair Muamba and Larsson doing the damage.
The visitors replied instantly when Liam Ridgewell went forward to nod on a corner by Larsson - and Muamba reacted quickest to stab a shot past David James.
It was breathless stuff to warm a chilly night on the south coast and the tackles were soon flying in - with Birmingham captain Damien Johnson lucky to escape a booking when cutting down Pedro Mendes.
But there was no contact at all in referee Steve Tanner's clear view, when Mauro Zarate went tumbling over Glen Johnson's challenge - and was booked for diving.
Goalkeeper Taylor saved Birmingham slipping two goals behind again when keeping out Papa Bouba Diop's long-distance strike just after the quarter-hour mark.
Delicious
But Pompey lost their early verve and five minutes from the break, Forssell - whose hat-trick sunk Tottenham last time out - went down down just outside the area following a soft challenge by Glen Johnson.
Larsson curled a delicious free-kick out of James' reach to put Birmingham - unbeaten in their previous four games - level.
Four minutes after the interval the visitors' defence buckled again when Ridgewell failed to clear a long, dipping free-kick from Muntari - aimed at the considerable figure of Diop - and allowed Hreidarsson to score.
Pompey might have had another penalty after 64 minutes when Ridgewell appeared to trip Baros from behind as the Czech went in pursuit of Johnson's through pass following a determined run by the right-back - but Tanner opted not to give a penalty to the Czech - although he escaped Zarate's earlier yellow card fate.
Birmingham brought on McFadden for Zarate just after the hour but Redknapp sharpened up his resources with the introduction of Lassana Diarra and Kanu soon afterwards.
City substitute Cameron Jerome - on for Forssell - came closest to equalising again, with a shot from Larsson's cross bringing a fine save out of James.
And, right at the end, Kanu polished off the visitors when he dived to head in Mendes' cross - his first goal since October.
