Freddie Burns suffered a nightmare pick-pocket that ultimately cost Bath the game as Toulouse continued English clubs' painful start to the Heineken Champions Cup by claiming a 22-20 victory over Bath.
Less than 24 hours after European title holders Leinster crushed Wasps under a half-century of points in Dublin, Toulouse clinched a crucial Pool One win at the Recreation Ground.
And they were helped by Bath full-back Burns, who missed an easy 74th-minute penalty chance and then blew a try barely 60 seconds later after crossing the Toulouse line before having the ball tapped out of his grasp by lurking Toulouse defender Maxime Medard, who had snuck around his blind side.
Had he dotted down, Bath would have led 25-22 with a conversion attempt to come.
Centre Sofiane Guitoune scored two tries for Toulouse, including a clincher 17 minutes from time, while wing Medard also touched down and full-back Thomas Ramos kicked two conversions and a penalty.
Burns was disconsolate at the final whistle, burying his head in his hands. He and centre Jamie Roberts looked to have sent Bath on their way with first-half tries.
But Wales international Roberts did not appear for the second period after being on the receiving end of a Jerome Kaino tackle that saw the New Zealand World Cup winner sin-binned, and Bath missed his physical presence.
Despite Burns adding 10 points from the boot, four-time European champions Toulouse capitalised on his profligacy, and closed the game out to leave Bath already facing a mountain to climb in terms of any quarter-final aspirations.