Bath's woes continued as they were beaten by Harlequins for a sixth league loss in eight games this season.
Alex Dombrandt put Quins ahead early, ending a fine passing move, before Aaron Morris got a deserved second as the visitors dominated the first half.
Bath's Tom Dunn got a try back soon after the restart but Danny Care replied for Quins while Bath had two players in the sin bin.
Tom De Glanville got a late consolation for the hosts after sustained pressure.
Bath stay 10th in the Premiership, but could drop further should Gloucester win at London Irish, while Quins move up to fourth place.
After exchanging early penalties, Quins burst into life with a wonderful eight-pass move from 10 metres inside their half which saw Dombrandt go over after quick hands between Louis Lynagh, Mike Brown and Care down the right wing.
Penalties from Marcus Smith and James Lang put the visitors further ahead, Bath giving away a number of infringements at the breakdown as they struggled to gain a foothold in the half.
Dombrandt had a second try ruled out after 26 minutes when he grounded the ball short of the line, but Morris got his first score of the season a few minutes later when he darted in from the left as Quins laid siege to the Bath line.
Bath started the second half brightly and Dunn was mauled over from close range following a five-metre line-out.
But any hopes to get further back into the game evaporated in a two-minute spell 10 minutes into the second half - first Semesa Rokoduguni was sin-binned for a deliberate knock-on, then Care darted over from close range for the third try with Sam Matavesi yellow carded for a high tackle on Care as he went over.
Bath turned the ball over when close to the Quins line a number of times and only got over in the final five minutes when De Glanville found himself on an overlap wide on the left after Bath pressure on the visitors' line.
The hosts nearly secured a losing bonus point in the final minute, but full-back De Glanville was tap-tackled a metre from the whitewash.
Bath director of rugby Stuart Hooper:
"Let's not move away from the fact we are here to win games, but there are massive positives to take.
"We showed a lot of resilience when we went down to 13 and there were a lot of young players out there who were getting their first real taste of Premiership rugby.
"If you look at the game, ultimately our discipline cost us. We conceded six penalties in the middle of the first half and then two yellow cards in the second.
"When you are on a run of losing games it's not all about clinging on to the positives, but I'm massively proud of the performance. We need to harness this energy because although we didn't win, the boys came together."
Harlequins attack coach Nick Evans:
"It was good to back up the Wasps win with another good performance. We were good for 50 to 60 minutes, but not for the last 20.
"I was really happy with the work rate and physicality and we started really well which is something we had talked about. Now we want to try and find an 80-minute performance."
"After the Wasps game people were wondering if we would be typical Harlequins and be up and down like a yo-yo so it's good to get another win.
"We are under no illusions the Premiership is very competitive and there will be peaks and troughs. At the moment we are on a peak and we've got to maintain that."
Bath: De Glanville; Rokoduguni, Clark, Matavesi, Cokanasiga; Priestland, Spencer; Schoeman, Dunn, Judge, McNally (capt), Williams, Bayliss, Reid, Mercer.
Replacements: Walker, Bhatti, Verden, Richards, Staddon, Chudley, Schoeman, Muir.
Harlequins: Brown; Lynagh, Marchant, Esterhuizen, Morris; Smith, Care; Marler, Baldwin, Louw, Symons, Lewies (capt), White, Evans, Dombrandt.
Replacements: Elia, Garcia Botta, Kerrod, Young, De Carpentier, Landajo, Lang, Green.
Referee: Craig Maxwell-Keys (RFU).