Craig Gardner dented Tottenham's chances of cementing a place in the Barclays Premier League top four with a late equaliser for Birmingham in a 1-1 draw at St. Andrew's.
Spurs had looked the better side in the opening period and deservedly took the lead through Sebastien Basson's first goal for 16 months.
But Gardner salvaged a point for the Carling Cup semi-finalists 10 minutes from time with his fifth goal of the campaign.
Spurs started to take control and Blues defender Scott Dann got in an important tackle on Jermain Defoe after a one-two with Peter Crouch.
Liam Ridgewell was yellow-carded after 18 minutes for bringing down Gareth Bale and - from the resulting free-kick - Spurs went ahead. Ben Foster got a touch on Bale's inswinging free-kick but Bassong was first to react and hammered home.
Blues were looking vulnerable and another dangerous cross from Aaron Lennon picked out Bale, but he failed to make proper contact with his volley.
Gardner burst forward and drilled a low cross-shot just wide and Lee Bowyer outwitted Wilson Palacios, but his shot was well off the mark. Defoe had a fierce drive deflected just wide and a header from Gardner was saved.
Stephen Carr produced a good tackle to halt Defoe in the box as he chased down a Crouch throughball.
Defoe turned inside Liam Ridgewell and Roger Johnson but screwed his low shot wide and, after William Gallas blocked a shot from Cameron Jerome at the other end, Foster beat out a Bale effort and Defoe scuffed wide.
Heurelho Gomes superbly denied Ridgewell at close range but Blues were not to be denied. Johnson's deep free-kick was headed back across and Gardner timed his run perfectly to head his fifth goal of the campaign.