Bath finished the game with 11 men as they suffered defeat to lowly Worcester Warriors in the 98th minute.
Worcester Warriors clinched only their fourth victory of the Premiership season as Bryce Heem scored a 98th-minute try against a Bath side who finished the game with 11 men.
Second bottom in the table, the Warriors appeared set for a heavy defeat as Bath stormed to a 19-3 half-time lead, 14 of their points coming from the boot of Freddie Burns.
However, Duncan Weir's penalty was followed by Heem's first try as Worcester cut the gap to eight points before the game turned further in their favour as Ross Batty was sent off for a neck roll.
Weir then knocked over another penalty to bring Worcester to within a try, with the Warriors subsequently piling on the pressure just a few metres out from the Bath line as Todd Blackadder's men tried desperately to protect their advantage.
But Max Lahiff, Lucas Noguera Paz and Aled Brew all saw yellow in the additional minutes, and a severely depleted Bath were unable to hold out as a long looping pass found Heem to touch down and Weir added the crucial conversion.
Worcester are now four points ahead of Newcastle Falcons after the bottom side were beaten again.
Harlequins celebrated Mike Brown's club-record 308th appearance in style by running in five tries in a 38-17 defeat of the Falcons to go third.
They leapfrog Gloucester following their disappointing defeat to Leicester Tigers. Jonny May scored twice against his former club and George Ford tallied 19 points for Leicester in a 34-16 triumph.
Leaders Exeter Chiefs survived a surprisingly tough test to go four points ahead of Saracens after their defeat to Sale Sharks on Friday.
Struggling Bristol were not expected to put up much of a fight against the Chiefs, who have contested the last three finals, but provided admirably stern resistance.
Exeter led just 7-3 at the break courtesy of Santiago Cordero's try on the stroke of half-time. However, a pair of Ian Madigan penalties gave Bristol a slender two-point advantage.
Yet Sean Lonsdale's try 14 minutes from time proved decisive in settling a hard-fought contest for the Chiefs.