Manchester United moved within five points of league leaders Manchester City after coming through a late scare at Vicarage Road.
Two goals from former Hornets winger Ashley Young and a strike from Anthony Martial handed the Red Devils a healthy half time advantage that looked set to seal a comprehensive win.
But the hosts threatened a comeback when Troy Deeney scored from the penalty spot before Abdoulaye Doucoure added a second.
A draw looked to be on the cards before Jesse Lingard settled the visitors’ nerves with a fine counter-attack to seal maximum points.