A David Unsworth penalty earned Portsmouth a draw against a new look Birmingham side at Fratton Park.
Midfielder Robbie Savage gave the visitors the lead when he curled home a 25-yard free-kick.
But Birmingham's Stan Lazaridis was adjudged to have pushed Pompey's Steve Stone to earn the home team a penalty which Unsworth belted in.
Keeper Shaka Hislop saved well to deny Emile Heskey while Maik Taylor did the same at the other end from Yakubu.
Birmingham's side included their four summer signings - Heskey, Jesper Gronkjaer, Mario Melchiot and Muzzy Izzet.
And, after an opening 10 minutes of sparring, the visitors landed the first blow through midfielder Savage.
Damien Johnson was brought down just outside the penalty box by Richard Hughes allowing Savage to step up and curl home a free-kick.
But Portsmouth's form at Fratton Park was a major reason behind their Premiership survival last season and they were level six minutes later.
Unsworth (right) levelled for Portsmouth from the spot
Home debutant Unsworth powered in a spot-kick after Lazaridis was adjudged to have pushed Stone as the pair challenged to head a cross.
A flurry of action then saw Martin Taylor breathe a sigh of relief when the referee did not rule his tackle on Yakubu as a professional foul and only gave the Birmingham defender a yellow card.
Pompey keeper Hislop was not happy at earlier letting in Savage's free-kick and atoned for not saving it when he saved a header from an unmarked Heskey low to his right.
Izzet blazed the rebound high before Blues keeper Taylor came to his side's rescue at the other end.
Yakubu raced onto a Patrik Berger through ball only to see his side-foot effort is diverted wide by Taylor.
Blues striker Forssell was given a clear sight of goal after a mistake by the Pompey defence but his low left-foot strike was saved by the long legs of Hislop.
Chances were not as frequent after the break though Portsmouth had more of the upper hand.
But it was Birmingham
who almost took the lead when Lazaridis cut inside from the left flank before firing a shot agonisingly wide.
Birmingham thought they should have had a penalty because of a Linvoy Primus handball but their appeals were waved away.
Steve Bruce's side were mainly a threat on the counter attack and endured some anxious moments
But Clinton Morrison's swivel and shot could have won it for them with virtually the last kick of the match.
Portsmouth: Hislop, Primus, Stefanovic, De Zeeuw, Unsworth,
Stone (Griffin 85), Quashie, Hughes, Berger (Taylor 81),
Subs Not Used: Ashdown, Berkovic, O'Neil.
Booked: Hughes, Unsworth.
Goals: Unsworth 16 pen.
Birmingham: Maik Taylor, Melchiot, Martin Taylor, Upson,
Lazaridis, Johnson, Izzet, Savage, Gronkjaer (Gray 67), Heskey,
Forssell (Morrison 90).
Subs Not Used: Bennett, John, Clapham.
Booked: Savage, Martin Taylor, Lazaridis, Izzet.
Goals: Savage 10.
Ref: H Webb (S Yorkshire).