Ruaridh McConnochie produced two classy finishes to ruin Harlequins' celebrations over the temporary return of their fans as Bath emerged 41-27 winners at Twickenham Stoop.
A crowd of 2,700 attended the test event – the first time supporters have been at any Gallagher Premiership match since the five-month interruption caused by Covid-19.
And while the pilot for rugby appeared to be a success, inspiring Quins to seek permission to stage another as soon as possible, events on the pitch took the gloss off the afternoon.
Apart from a blistering start that produced an early try for Joe Marchant, they were totally outgunned by play-off-chasing Bath who had galloped out of sight two minutes into the second half.
It was McConnochie who delivered that killer blow as one of two tries seized with Eddie Jones watching from the stands and England's head coach can only have been impressed by his clinical touch.
Picked as a bolter for the 2019 World Cup, the 28-year-old Olympic silver medallist suffered a drop in form upon his return from Japan but his post-lockdown haul of five tries in four games propels him into contention for the autumn.
Adding to the wing's try-scoring efficiency was a masterful kicking display by Rhys Priestland, the Wales fly-half who finished the bonus-point triumph with an individual 21-point haul
Error-strewn Harlequins never recovered from seeing McConnochie capitalise on a restart blunder to ignite Bath and all energy drained from their game, exposing a lack of resilience and belief.
Roared on by their soon-to-be muted fans, Quins made a high-octane start that underlined their determination to mark the occasion with a show.
Brett Herron produced a couple of early flourishes but it was his half-back partner Danny Care who set-up Marchant's sixth-minute try with a hanging kick that descended in front of the posts.
Showing his aerial athleticism, Marchant won the mid-air duel and then showed the strength to drive over the line and touch down.
Two Herron penalties pushed Harlequins into a promising lead but the second of those brought with it disaster as from the ensuing restart Matt Symons made a hash of the kick, spilling it backwards.
McConnochie reacted in a flash by beating Chris Ashton to the ball and the England wing produced a skilful finish under pressure.
Quins were shaken by the self-inflicted challenge to their dominance and it took only five minutes for them to crack again as Bath rumbled over through Elliott Stooke once centre Cameron Redpath had carved a hole in midfield.
With Priestland on target, the west country visitors cruised 23-13 ahead and their opponents' frustration was clear when Care took a quick penalty only for the ball to be lost at the ensuing ruck.
Early in the second half Bath were out of sight as McConnochie claimed his second try when space was created down the left by a slick interchange and the former sevens specialist sprinted over, finishing with a side-step.
Martin Landajo and Lewis Boyce exchanged tries in a final quarter that lacked intensity due to Bath's unassailable lead and Quins repeatedly dropping off-loads until James Lang touched down in injury time.
