Danny Ings struck a double and left Ben Foster red-faced as Southampton roared to a 3-1 win at relegation-threatened Watford.
Former England goalkeeper Foster was making his 100th consecutive Premier League appearance but blundered for Ings' second goal at Vicarage Road, before James Ward-Prowse wrapped up the points with an exquisite late free-kick.
Ings got Southampton's first goal in the 16th minute when he whipped a fine low shot beyond Foster from 20 yards, before netting again in the 70th minute after intercepting a throw from Foster and sending a low shot past the veteran via a slight deflection off Craig Dawson.
That took Ings to 18 league goals for the season, just one behind Golden Boot frontrunner Jamie Vardy.
A Jan Bednarek own goal briefly narrowed the gap after 79 minutes, but set-piece specialist Ward-Prowse scored in style three minutes later, whipping the ball over the home wall and leaving Foster standing, with Watford still 16th, just a point outside the drop zone.