Wasps went second in the Aviva Premiership with a five-try 31-26 victory at Bath, who never recovered from falling 19 points behind in the first 23 minutes.
The home team scored four tries and picked up a losing bonus point, too, but they were always behind on the scoreboard.
They finished on the attack but flattered to deceive against a Wasps team whose skipper, Joe Launchbury, provided strong carrying and cool leadership at critical moments.
Kyle Eastmond's hopes of impressing against his former club were dashed when he was injured in the warm-up, leaving Fijian centre Gaby Lovobalavu to fill in.
But it was Bath who started more hesitantly, shipping penalties and making errors. It was no surprise when Marcus Watson nipped in at the corner to put the visitors ahead within eight minutes, Danny Cipriani adding the conversion.
With barely 10 percent possession and territory in the first quarter, a passive Bath defence invited punishment and scrum-half Dan Robson scrambled over for another try converted by Cipriani.
It was no surprise when Watson added a third unconverted score for Wasps on 23 minutes as Cipriani orchestrated affairs with crisp, well-timed distribution.
The scoreboard read 19-0 and it would have been more had Wasps been more accurate with the final pass.
The fact that Bath had an advantage in the scrum was little consolation but there was a glimmer of hope when Watson was sin-binned for a deliberate knock-on and Wasps' discipline began to desert them.
First Priestland crossed by the posts from a scrum, the fly-half converting his own try, and still Wasps conceded penalties. Bath suddenly held the whip hand and right wing Jack Wilson stepped Robson to touch down out on the right.
Priestland's conversion was good and, somehow, the home side found themselves trailing only 19-14 at half-time.
But Wasps struck with a bonus point try immediately after the break as Juan de Jongh finished off Robson's break from a ruck. Cipriani converted.
Bath shook off their lethargy and flanker Paul Grant finished off from close range after Paul Brew made the all-important bust, coming infield from the left wing. Priestland hooked the conversion.
Back came Wasps with a fifth try as Lovobalavu capitalised on sloppy defence. They then lost Willie Le Roux to the sin-bin for cynical play and the home side claimed a bonus point try through Zach Mercer, one of their brighter performers.