Bath ended a four-game losing run with a convincing victory over London Irish at the Recreation Ground.
The hosts took the lead through Anthony Perenise's try with Stephen Donald converting before adding a penalty.
Tom Homer responded with a penalty for the Exiles before Donald added three more points for Bath after the break.
A Michael Claassens score and penalty try, both converted by Donald and either side his third successful penalty sealed an impressive win.
Bath struck first after the television match official declared that Perenise had scrambled the ball over and Donald then added the first of three successful conversions.
And the Samoan tighthead almost forced the ball over for a second time before referee Martin Fox ruled there had been a knock-on after again consulting a video replay.
Donald then added a penalty before Homer responded with three points of his own for the Exiles.
A slip-up by Topsy Ojo looked to have let Olly Woodburn through but James Buckland's sliding challenge forced the Bath player into touch.
Donald's second penalty increased the host's lead to 10 points within the first five minutes of the second half before Claassens rounded off an 80-metre counter-attack to further extend the hosts' lead.
Nick Abendanon ran around Homer before offloading inside to Tom Biggs, who drew the covering defence and put Claassens clear for his 20th Premiership try.
New Zealand World Cup winner Donald then converted before adding a third penalty to put Bath 20 points in front and on their way to avoiding their worst run in the Premiership for 10 years.
Former St Helens scrum-half Kyle Eastmond came on for his rugby union debut playing on the wing after replacing Woodburn before Bath were awarded a penalty try, which was again converted by Donald.
The Exile's misery was compounded when England international full-back Delon Armitage was sin-binned for a late tackle on Claassens.
Bath's previous Premiership victory had been in the reverse fixture against Irish at the Madejski Stadium on 29 October.
Bath rugby director Sir Ian McGeechan:
"We put a good game together. We had done it for spells in games, but not for 80 minutes.
"We kept control of the game today, and the result was in our hands going into the last 20 minutes. That makes a big difference.
"The scrum was outstanding, but people like Nathan Catt and Anthony Perenise are also natural ball-carriers.
"It wasn't ever going to be a really quick game because of the conditions, but we had eight forwards comfortable in ball-carrying positions."
London Irish head coach Toby Booth:
"We didn't come up with enough answers, and quite often we gave away too many gifts.
"When you have got a side that is desperate to get on the winning trail, like Bath were, and the conditions being like they were, it made it very difficult.
"We put ourselves under unnecessary pressure, and that is really disappointing.
"This is the most competitive league going, we all know that, but the good thing is you get a chance to put it right straight away.
"We have Sale next, and we are going to need to show our character and bounce back. We will find a lot out about ourselves this week."
Bath: Abendanon; Woodburn, Carraro, Banahan, Biggs; Donald, Claassens, Catt; Batty, Perensie; Attwood, Caldwell, Beattie; Louw (captain), Taylor.
Replacements: Eastmond for Woodburn (68), Beech for Catt (67), Wilson for Perenise (59), Skirving for Beattie (62).Not Used: Tanner, Mercer, Cook, Heathcote.
London Irish: Armitage; Ojo, Ansbro, Hape, Horner; Shingler, Allinson, Corbisiero; Buckland, Ion; Kennedy, Evans, Danaher (capt); Gibson, Thorpe.
Replacements: Jarvis for Ansbro (57), Thompstone for Homer (78), Hodgson for Allinson (66), Dermody for Corbisiero (56), Paice for Buckland (56), Lahiff for Ion (66), Gray for Gibson (69), Garvey for Thorpe (33).
Referee: Martin Fox (RFU).