George Ford booted 24 points as Bath kept the pressure on Northampton at the top of the Aviva Premiership with a 39-16 victory over rivals Gloucester.
Ford was outstanding, landing six penalties and converting a penalty try and both of Matt Garvey's two touch downs, as his side claimed their biggest-ever Premiership win a t Kingsholm.
Despite putting Bath under pressure at times, Gloucester could only record three penalties from scrum-half Greig Laidlaw's boot and a try from his replacement Dan Robson, which was converted by fly-half James Hook.
Bath arrived at Kingsholm after a national newspaper report claimed that they are being investigated, along with Saracens, for breaches of the Premiership salary cap on Saturday.
Nothing has been confirmed about the allegations, which Premiership Rugby refused to comment on when asked by Press Association Sport, but it was not the ideal build-up to a big West Country derby clash for the men from The Rec.
Sam Burgess, Bath's biggest signing of the season, was on the bench for the derby after starting in the centre against Montpellier in the European Challenge Cup seven days earlier.
And, in front of a sell-out crowd, Gloucester were intent on adding to Bath's frustrations as they controlled the early territory but only had two Laidlaw penalties in the opening 17 minutes to show for their dominance.
Bath pulled themselves together and as they hassled Gloucester in midfield, mistakes saw Ford come to the fore.
The England international was in wonderful form with his clinical goal-kicking, despite an unexpected simple handling error in the first-half that had the home fans cheering.
It was intense stuff between the old rivals, with outstanding defence on both sides keeping their goal-lines unbroken.
Ford and Hook tested the opposition under high balls on numerous occasions, looking for the mistake that could lead to a try, but when there was one England ace Matt Banahan was brought down close to the line after making a dart for the left corner.
Gloucester had penalty attempts to get them back on terms but both Laidlaw and centre Billy Twelvetrees missed the posts, before the Scottish scrum-half finally landed a third goal when David Wilson was penalised at a set-piece.
However, it was Ford who was the keystone of the half, hitting the Cherry and Whites for 15 points before the break via five penalties - most of which were from medium to long range.
Gloucester started the second half on the front foot - a mirror image of the first period - as they developed countless phases inside Bath territory, but again Bath's outstanding defence was rock solid and turned the ball over to clear the danger.
Ford made it six penalties when replacement loose-head prop Nick Wood took a scrum down on his own 22 and, suddenly, Gloucester were nine points down and in desperate need of a converted try.
But, after replacement tight-head Sila Puafisi, who was sent off in the ugly affair between the two teams last April, was sin-binned for taking down a scrum, Bath powered their way to the line.
Gloucester took down the maul and referee Greg Garner went under the posts to award a penalty try.
Again Bath's tremendously organised defence would not be breached as Gloucester again powered within the visitor's 22.
But when Garvey got Bath's second try, moments before Burgess came on in place of England wing Semesa Rokoduguni, it was all over for Gloucester.
Finally, Gloucester breached the Bath line as Robson stormed in from 22 metres, with Hook converting, but it was too little too late as Garvey got a second converted try in the last move of the match.