The Blues full-back landed four penalties and though Leigh Halfpenny added a crucial fifth kick two minutes from time, it was Blair’s late catch and clearance that sealed the win.
Florian Fritz, Frederic Michalak and David Skrela all struck for Toulouse but a raft of handling errors saw the French giants slip to their first Heineken Cup defeat of the season.
Cardiff defeated the same opponents in last season’s quarter-final and this win went some way to keeping alive their hopes of progressing to that stage again from a fiercly contested Pool Five that includes Harlequins and Sale Sharks.
They led 6-0 at half-time through two Blair penalties though there were times when they rode their luck as an all-star French back-line misfired in the cold.
The unlikely boot of Martyn Williams came closest to creating the game’s first try. The canny flanker spotted Leigh Halfpenny lurking out wide but Shaun Sowerby galloped across to side-foot the ball out of play as the Wales wing bore down to score.
The Blues lost an edge in attack when Tom Shanklin left the field mid-way through the first half though Toulouse’ handling errors failed to make possession count and Blair opened a 9-0 lead four minutes into the second half.
Fritz and Blair exchanged further kicks in a game of precious few scoring opportunities before Michalak and replacement Skrela set up a tense final ten minutes as 12-9. Fritz missed the chance to equalise before Halfpenny settled it late on.
