Bath's hopes of making the Premiership play-offs were severely dented as Worcester Warriors significantly boosted their bid to avoid relegation with a 25-19 victory at Sixways.
Todd Blackadder's Bath had drawn level on points with fourth-placed Leicester by beating the Tigers at Twickenham last weekend, but lost ground on Saturday.
Worcester's win - secured through second-half tries from Josh Adams, Wynand Olivier and Will Spencer - sees them close the gap on 10th-placed Sale Sharks to five points, with two rounds of the regular season remaining. The Warriors had not beaten Bath since November 2011.
A converted Matt Banahan try put Bath 10-3 up at half-time, but the visitors ultimately required George Ford's fourth penalty of the match, in the 79th minute, just to secure a bonus point.
Bath are now four points adrift of Leicester after the latter came on strong in the second half to beat Newcastle Falcons 30-3 at Welford Road.
After a try-less opening period, Ellis Genge crossed twice for the Tigers, while there were also touchdowns for Telusa Veainu and Ben Youngs.
Sale, victors over Worcester eight days earlier, led for much of the second half at Gloucester, only to be beaten 39-30.
Mike Phillips was one of four try-scorers for Sale, in the week the former Wales international announced he will retire at the end of the season.