Investec Champions Cup Pool 2
Bath: (21) 40
Tries: De Glanville, Russell, Cokanasiga, Du Toit 2, Lawrence Cons: Russell 5
Clermont Auvergne: (14) 21
Tries: Fainga'a, Belleau, Yato Cons: Belleau 3 Red card: Akhaladze
Bath breathed life into their Investec Champions Cup campaign with an impressive bonus-point victory over 14-man Clermont Auvergne at the Rec.
Finn Russell was the architect of Clermont's demise, producing an influential display with ball in hand and from the boot, while the visitors lost prop Giorgi Akhaladze to a first-half red card.
Bath, who had lost their opening two games in Pool 2, raced into an early lead through Tom de Glanville's try before Russell created and finished their second soon after.
Clermont hit back as Folau Fainga'a powered over from close range, but the game changed when Akhaladze was sent off for making direct head contact with Bath centre Max Ojomoh.
The hosts punished Clermont two minutes later when Ojomoh claimed Russell's clever chip to feed Joe Cokanasiga for their third try.
Despite their deficit on the field, Clermont were rewarded for their resolve on the stroke of half-time as Anthony Belleau pirouetted over the line with a neat finish.
Thomas du Toit's surge under the posts secured the bonus after the break before the prop burrowed over from a similar distance for Bath's fifth try.
Clermont, who arrived at the Rec having beaten Benetton before losing at Leinster, remained committed and earned a deserved consolation through Peceli Yato, but the hosts had the final say as Ollie Lawrence grounded their sixth try in the corner.
Bath move from sixth to third in Pool 2 but face a daunting trip in their final game to four-time winners Leinster, who have already qualified for the knockout stages.
Fifth-placed Clermont leave the Rec empty-handed and host Bath's Premiership rivals Bristol in round four, with both sides still capable of qualification.
Bath signed Scotland fly-half Russell before the 2023-24 season in a deal reportedly worth £1m-a-year,, external with the clear objective of winning the biggest prizes.
Johann van Graan's side lead the way domestically but their form had not translated into Europe, with opening defeats by La Rochelle and Benetton.
Needing a win to kick-start their campaign, their talisman rose to the challenge.
It began in the second minute as Ojomoh latched on to the Scot's flat pass to split the Clermont defence for the initial break. Bath continued to drive forward and Russell fired another perfectly weighted pass for De Glanville to dive over for the opener.
The vociferous home support responded but the Scot was just getting started.
A master of deception, Russell then threw a dummy to create space for Cokanasiga to burst over the gain-line before getting his hands on the ball several phases later to glide past his man and score his side's second try.
If that was the nonchalant running rugby, next came the deft boot - as he lifted the ball over the onrushing Clermont defence for Ojomoh to clutch on to and send Cokanasiga over.
Five assured conversions from six attempts took Russell's points tally to 15 and Bath's credentials as contenders in this season's Champions Cup is likely to hinge on his form.
Bath: De Glanville; Cokanasiga, Lawrence, Ojomoh, McConnichie; Russell, Spencer (capt); Obano, Dunn, Du Toit; Roux, Ewels, Hill, Reid, Barbeary.
Replacements: Annett, Van Wyk, Stuart, Molony, Bayliss, Schreuder, Bailey, Staddon.
Clermont Auvergne: Newsome; Delguy, Fouyssac, Simone, Tauzin; Belleau, Jauneau; Akhaladze, Fainga'a, Montagne, Simmons, Yato, Tixeront, Kremer, Lee (capt).
Replacements: Fourcade, Lotrian, Ala'alatoa, Ceyte, Rixen, Bezy, Giral, Raka.
Referee: Mike Adamson (Sco)