An own goal by goalkeeper Heurelho Gomes helped earn Stoke City a deserved win as 10-man Watford suffered a first home defeat since August.
Gomes could do little as Charlie Adam's header from Xherdan Shaqiri's corner hit the base of the post before ricocheting off the Brazilian and rolling into the net.
If there was a touch of fortune about the goal, Stoke were full value for their victory against sluggish opponents who missed out on the chance to climb to sixth in the Premier League table.
Watford had Miguel Britos sent off in the closing stages for a second yellow card after Gomes had saved well from Bruno Martins Indi, while Stoke's club record £18.