Bath held off a second half comeback by London Irish to register a 20-16 victory at the Madejski Stadium.
London Irish failed at the death to send Bath packing in the Guinness Premiership as they went down to defeat at the Madjeski Stadium in Reading.
Irish could have expected a good afternoon after they pushed Leicester to within two points at Welford Road but, almost from the start of the match, the Exiles were on the back foot.
It did not help head coach Toby Booth either that he had seven men out of action through injury, although that was no excuse for a first half in which Bath punished too many mistakes.
And although visiting fly-half Butch James, who saw all five kicks go wide in his team's first home league defeat to arch-rivals Gloucester last week, began in the same vein he did manage to land two goals, one from in front of the posts and another from 30 metres.
It was a day when the boot again was a dominant factor in the contest. For Irish full-back Peter Hewat and fly-half Eoghan Hickey both missed two shots at goal which, if successful, would have given their team the advantage.
Bath went into the break 17-5 ahead after James had crossed for an early try when Bath got to within a metre of the opposition line before lively scrum-half Michael Claassens sent the South African number 10 through a gap from two metres.
Irish were given a man advantage on the half-hour when Bath centre and co-captain Alex Crockett was ordered to the sin-bin for fighting with home hooker David Paice.
They seized the opportunity, with skipper Seilala Mapusua playing a dominant role in most good things for the Irishmen.
Just before half-time Cumbrian referee David Pearson walked off with a back injury to be replaced by Berkshire's Ashley Rowden.
Irish needed a score before the break and they found it as they had Bath reeling on their own line for American-born loose-head prop Alex Corbisiero to drive over from a few metres and give his side a lifeline.
The Exiles could still not kick a goal and Hickey missed a fifth shot after 43 minutes but, eventually, Hewat raised his arm in the air when a 30-metre penalty finally found its target.
It gave Irish new momentum and again Mapusua and co-centre Delon Armitage were the instigators of a powerful attack which full-back Nick Abendanon just about got away to safety with the try-line begging.
A second Irish success at goal, this time Hickey landing a 40-metre shot, put them only six points behind and now that they were actually keeping some ball, winning good set-pieces and spreading it to their quick backs, Bath were heavily on the defensive.
Lock Bob Kennedy was the supplier of endless clean line-out possession as Irish pressed for the converted try that would give them victory.
With four minutes left Mapusua refused a 35-metre penalty in favour of a kick to touch and line-out which seemed to come to nothing, but after a few plays, Irish scored.
The ball came to the right wing and replacement Elvis Seveali, once a Bath man himself, chipped to the line and scored. Hickey could have put his team in front with the conversion but missed again.
And Bath sealed their second victory of the season when Jack Cuthbert booted his third penalty with seconds left.
London Irish (5) 16 Bath (17) 20
London Irish: Tries: Corbisiero, Seveali'i. Pens: Hewat, Hickey.
London Irish: Hewat, Ojo, D. Armitage, Mapusua, Tagicakibau, Hickey, Richards, Corbisiero, Paice, Rautenbach, Kennedy, Johnson, Thorpe, S. Armitage, Hala'ufia.
Replacements: Seveali'i for D. Armitage (56), Hodgson for Richards (59), Fisher for Corbisiero (70), Lea'aetoa for Paice (62), Coetzee for Rautenbach (59).
Not Used: Rouse, Thompstone.
Bath: Tries: James. Pens: James 2, Cuthbert 3.
Bath: Abendanon, Maddock, Crockett, Fuimaono-Sapolu, Cuthbert, James, Claassens, Barnes, Mears, Bell, Harrison, Short, Hooper, Lipman, Scaysbrook.
Replacements: Cheeseman for Crockett (65), Berne for Fuimaono-Sapolu (56), Bemand for Claassens (63), Flatman for Barnes (63), Dixon for Mears (55).
Not Used: Stevens, J. Ovens.
Sin Bin: Crockett (30).
Att: 10,000
Ref: David Pearson (RFU).