The midfielder last scored for the club in April 2003 but he struck twice inside 16 minutes to add to Steve Jones' opener as Crewe coasted to a 3-0 half-time lead.
Prior to their visit to the Alexandra Stadium, Ray Lewington's side had the meanest defensive record in the division.
But they were caught out by Jones in the 20th minute when the Northern Ireland international latched on to Kenny Lunt's pass and nudged the ball under the advancing Richard Lee.
The visiting keeper was picking the ball out of the net two minutes later after some shocking defending from his colleagues.
James Chambers failed to pick up Jones' left-wing run and it appeared Lee had saved the day when he blocked the striker's angled drive. But Watford failed to clear the line and when David Vaughan squared the ball across the six-yard box, Gavin Mahon inadvertently played it off Sorvel's legs into his own net.
Vaughan, who had missed a good chance to open the scoring when he shot straight at the keeper early on, whistled one over from 25 yards as Crewe took control of the game.
They went three up in the 38th minute when Sorvel claimed his second. Lunt's corner wasn't cleared by the Hornets defence, and with the ball bobbling around like a pinball machine, Sorvel's half-hit, half-volley trundled past the keeper who appeared unsighted by the ruck of players in front of him.
Anthony Tonkin almost put the game beyond Watford's reach just before half time when he picked up Dean Ashton's pass and smashed the ball inches over the bar.
Heidar Helguson missed a chance to reduce the arrears in first half injury time when he mis-kicked at the near post.
Crewe could have added more goals in the second half, but Watford missed gilt-edged chances which would have made the home side's passage to victory less comfortable.
Danny Webber missed a sitter from six yards out when he tamely fired into Ben Williams' hands, and then virtually on the goalline he was denied by a great last-ditch tackle from teenager Billy Jones.