It was no great surprise they lost their first match in eight to a spirited London Irish side, but what will concern head coach John Connolly was the sloppy nature of the defeat.
Two knock-ons, by Ryan Davies and Joe Maddock in the 21st and 25th minutes, gifted Irish two tries, scored by Scott Staniforth and the man of the match, Mike Catt. Soon after Andy Dunne, selected as fly-half in the morning when Chris Malone withdrew with a sore hip, threw a punch and was sent to the sin-bin. Clearly it was not an auspicious first half for Bath, but more worrying than all those misdemeanours was their line-out.
In recent weeks it has been the proverbial well-oiled machine. Lee Mears has been hitting his jumpers, Danny Grewcock and Steve Borthwick. But with these three away with England it was a case of Pieter Dixon failing to hit anything.
Players have bad days, and knock-ons and such are curable in following games, but without a primary source of possession it is difficult to see Bath winning a match in the next month.
If that happens the optimism generated last week with the announced return of Brian Ashton as coach from 1 January will have completely disappeared before he has spent a day "back home'', as the locals consider it. They remember his work with the all-conquering Bath side of the 1980s, but to emulate those triumphs he will need to be a miracle worker.
For the Irish it was an important win, with a crucial bonus point. Dominant in the second half, their No 10 Riki Flutey scored their third try after the forwards had skilfully recycled possession a dozen times. Then Phil Murphy barged over in the corner.
Those scores suggested that Irish could increase their ambition. Bath, despite a late try by Michael Lipman, have a difficult month ahead.
London Irish: M Horak; S Staniforth, R Penney, M Catt (capt), D Armitage; R Flutey (B Everitt, 69), P Hodgson (B Willis, 53); N Hatley, A Flavin (D Coetzee, 64), F Rautenbach (R Skuse, 63), B Casey, N Kennedy (R Strudwick, 71), K Roche, P Murphy (P Gustard, 71), D Danaher.
Bath: L Best (N Abendanon, 55); J Maddock (S Davey, 69), A Higgins, R David, F Welsh; A Dunne, N Walshe (A Williams, 60); D Barnes, P Dixon (R Hawkins, 69), D Bell (C Loader, 79), J Hudson, R Fidler, A Beattie (cap), I Feau'nati (G Delve, 65), J Scaysbrook (M Lipman, 53).
Referee: R Debney (Leicestershire).