Derby County surrendered their position as Championship leaders as they lost to mid-table Brentford in the dying seconds of the match.
The Rams controlled the opening stages and almost took the lead with five minutes on the clock as Simon Dawkins surged into the Bees box and fired a shot into the side-netting.
Steve McClaren's side threatened again in the eighth minute. Chris Martin managed to get a shot away from the edge of the box, but his curling effort ended up the wrong side of the post.
Derby turned their dominance into a goal in the 26th minute when Craig Forsyth's measured cross was turned in off the post by Martin, whose tally for the season now stands at 12.
The Coldplay frontman's namesake almost had a second just after the half-hour mark, but his flicked effort was saved by David Button as Brentford kept their deficit at one come the interval.
McClaren's men were left ruing their missed chances early in the second period when the Bees drew level through Andre Gray, whose curling effort beat Jack Butland and found the top corner.
Derby continued to ask most of the questions, but it was Brentford who came close to a second in the 68th minute when Alan Judge's cross was headed against the post by Gray from close range.
Just as the match looked to be heading for a draw, the Bees snatched all three points in stoppage time as Stuart Dallas lashed a strike into the top corner to knock Derby off their Championship perch.