Falkirk condemned Celtic to their second SPL defeat in succession as Steven Thomson secured a valuable three points in a 1-0 win for The Bairns.
The title may be a foregone conclusion but The Bhoys' pride will still have been stung by a shock result.
Gordon Strachan's side missed a host of chances - including a first-half penalty - in a game that saw both teams reduced to ten-men before the break.
Falkirk survived an early scare when Shunsuke Nakamura fizzed a shot just wide of the upright, but The Bhoys were gifted the chance to take the lead on six minutes when Dean Holden hacked down Craig Beattie (pictured) in the box.
The young striker stepped up to take the resultant penalty, but could not direct his spot-kick far enough away from Kasper Schmeichel as the on-loan Manchester City keeper clasped the ball at the second attempt.
Beatie was appealing for another penalty when Darren Barr appeared to make contact with him in the box, and Celtic continued to pile on the pressure when Paul Hartley's free-kick struck the post after dipping through a crowd of players.
However, on 16 minutes, Falkirk hit the Glasgow giants with a sucker punch when Thomson met Carl Finnigan's neat cross from the right with a well-directed header after a surging run into the box.
In a full-blooded contest, both sides were reduced to ten men when Stephen McManus and Finnigan were dismissed following a clash of heads and elbows on the edge of the box.
With three minutes to go of the first half, Barr produced a fine block to deny Kenny Miller and ensure that Falkirk went into the break in the ascendancy.
Gordon Strachan's men continued to press after the break and Nakamura was appealing in vain for another penalty after contact from Patrick Cregg.
Beattie could only find the side-netting from a tight angle and Steven Pressley wasted another good chance when he hooked over from eight yards.
Falkirk substitute Pedro Moutinho went close on two occasions and The Bairns managed to hold on for a valuable win that sees them move to seventh in the table.
Click below for match summary:
Falkirk 1-0 Celtic