Blues defender Roger Johnson began an eventful afternoon at the Reebok Stadium with an early opener before getting involved in an incident that saw Bolton goalkeeper Jussi Jaaskelainen sent off. Johnson had challenged Jaaskelainen for the ball just before half-time and the Finn appeared to slap him in the face as they regained their feet.
Craig Gardner doubled Birmingham's lead but Bolton responded to the challenge to maintain their unbeaten start to the campaign. Davies replied with a penalty after a foul by the ubiquitous Johnson and veteran Blake levelled with a stunning late free-kick.
Both sides went into the game with confidence after collecting four points each from their opening two games. Changes were minimal with Bolton fielding the same XI that beat West Ham last week and Birmingham bringing in the influential Lee Bowyer for Nikola Zigic.
The visitors made the perfect start as Johnson handed them a lead after a fine move in the fourth minute. Bowyer pulled the ball back from the byline after being played through by James McFadden and Cameron Jerome flicked the ball into the path of Johnson, who slid in to score from six yards.
Yet as impressive as Birmingham's interplay had been, they were almost caught by Bolton's more direct approach just two minutes later. Davies leapt highest to flick on a long ball and Johan Elmander burst into the area only to lash a glorious chance for a quick equaliser wide.
Martin Petrov seized on a slip by Stephen Carr to get in another shooting opportunity but the Birmingham captain got back to block. Petrov found more space outside the area soon after but his next shot was deflected and Ben Foster saved.
At the other end Gardner drilled the ball into the net but Kevin Friend's whistle had already gone for a foul on Zat Knight. Jerome then appealed for a penalty after claiming Elmander had impeded him while trying to take a shot but Friend was not interested.
Bolton then broke upfield and Petrov won a free-kick after being brought down by Johnson. Stuart Holden curled the resulting set-piece at goal but Foster palmed over the bar. Gary Cahill, Petrov and Elmander all had shooting opportunities as Birmingham struggled to clear their own box but the ball was passed, sliced and then missed completely by the three players concerned.
Birmingham should have made them pay as they hit Bolton with a quick counter-attack but McFadden volleyed straight at Jaaskelainen after being picked out unmarked by the breaking Gardner. Jaaskelainen was dismissed eight minutes before the interval after being knocked over by Johnson. When he got up he clearly raised his hands to Johnson's face and Friend had no option but to show a red card.
Chaos momentarily broke out and Johnson was booked after getting involved with Petrov. When calm was restored, Petrov was sacrificed by manager Owen Coyle as substitute goalkeeper Adam Bogdan was sent on.
Bolton's 10 men were left facing an uphill struggle after Birmingham claimed a controversial second goal five minutes into the second half. Jerome looked fractionally offside as McFadden crossed into the area but the flag stayed down as the striker headed back across the six-yard box. With the Bolton defence static, Gardner was the first to react and he prodded the ball past Bogdan at the second attempt following a miskick.
Elmander had a chance to pull one back but was thwarted by a good Foster save after getting on the end of a low cross from Lee Chung-yong. Bolton appealed for a penalty by claiming Gretar Steinsson was impeded at a corner by Bowyer but nothing was given. But Friend did point to the spot 21 minutes from time as Johnson was penalised for climbing on the back of Davies.
The Bolton skipper emphatically reduced the deficit as he thumped the ball into the top corner. The hosts increased the pressure and levelled nine minutes from time after Cahill was fouled on the edge of the area by Barry Ferguson.
Summer signing Blake, a 67th-minute replacement for Elmander, stepped up to curl in a brilliant equaliser. Davies almost grabbed a late winner but blasted wide from inside the box. Jerome had a chance in injury time at the other end but Bogdan blocked with his feet.