Darren Bent gave the hosts the lead from the penalty spot in the 24th minute after Stephen Carr fouled Fraizer Campbell, and the veteran full-back headed the ball over his own keeper 11 minutes after half-time to put Sunderland two up.
By that point the hosts were already a man down following two yellow cards for new captain Lee Cattermole in the first half and the visitors eventually took full advantage, with Scott Dann heading in a soft first and Liam Ridgewell grabbing the equaliser two minutes from time.
Sunderland boss Steve Bruce gave full debuts to keeper Simon Mignolet, defenders Nedum Onuoha and Titus Bramble and winger Ahmed El Mohamady while John Mensah also started after returning to the Stadium of Light on loan from Lyon for a second successive season.
Birmingham's side had a more familiar look about it, although there was a debut in goal for Ben Foster after he overcame a back problem that forced him out of England duty.
The home side had much the better of the opening quarter of an hour without troubling Foster, who was able to watch a Steed Malbranque shot sail past his near post from the best chance.
There was then a break in play while Garry O'Connor received treatment after an accidental elbow from Cattermole caused a nasty cut above the striker's eye. The Scot was bandaged up and was able to continue.
Chances were few and far between but suddenly a break from Bent set Sunderland away. Referee Anthony Taylor waved play on when Dann looked to have fouled the striker and, as Campbell surged into the area, he was felled by Carr.
Taylor immediately pointed to the spot and, after he had shown Carr a yellow card, Bent stepped up to power the penalty into the bottom corner with 24 minutes gone.
Bent and Campbell were linking up superbly and last season's leading scorer should have grabbed his second five minutes later after a neat backheel from his strike-partner sent him into the area but he mis-hit his shot well wide from 10 yards.
Birmingham had yet to muster any kind of effort on goal and they nearly put themselves in even more trouble with 35 minutes on the clock.
El Mohamady beat his man but his cross looked set to be dealt with by Bowyer only for the midfielder to slice his clearance at Foster, who did well to keep it out at point-blank range.
Sunderland's day had been going exactly to plan but they found themselves reduced to 10 men two minutes before half-time when new captain Cattermole, who had earlier been booked for a foul on Cameron Jerome, clattered Bowyer from behind and was sent off.
Birmingham boss Alex McLeish would have expected much more from his team and he responded by bringing on James McFadden for Keith Fahey.
The visitors looked much brighter at the start of the second half and it needed a great tackle from Mensah to stop Jerome as he headed towards goal.
Sunderland's threat was now sporadic but in the 56th minute they went two up thanks to another nightmare moment for Carr.
Having conceded the penalty in the first half, the veteran right-back stretched to get a head to Jordan Henderson's free-kick under pressure from Campbell only to direct it over his own keeper and into the net.
McLeish made his second change immediately, bringing on 6ft 8in striker Nikola Zigic for his debut in place of O'Connor. And the Serbian almost grabbed a goal moments later but his 25-yard drive was well tipped over by Mignolet.
Cristian Riveros then came on for his Sunderland debut but, with 12 minutes to go, Birmingham were back in it thanks to another act of charity.
The visitors worked a short corner and Sebastian Larsson swung in a cross from the left that was headed down by Scott Dann and right through Mignolet.
The centre-back should then have levelled matters but he somehow failed to connect with Larsson's free-kick from six yards out with the goal gaping.
Danny Welbeck became the sixth Sunderland debutant in place of Bent but the pressure on the hosts was growing and inevitably it was another Larsson set-piece that provided the equaliser two minutes from time.
The Swede swung in a ball from the right that evaded everyone before finding Liam Ridgewell at the far post.