Anthony Martial scored on his return to the Manchester United lineup as Jose Mourinho's men moved to within a point of neighbours Manchester City with a 2-0 win over Watford at Old Trafford.
Zlatan Ibrahimovic had a chance to give United the lead in the opening moments when a deflected Antonio Valencia cross fell for him, but the Swedish striker miscued his volley and saw the effort bobble wide of the post.
Ibrahimovic was denied by a fine save from Heurelho Gomes, but United broke through after 32 minutes when a low cross from Martial eluded the striker but fell for Juan Mata to sidefoot home and give Jose Mourinho's side a deserved advantage.
Martial was in the thick of the action again when his low cross just failed to find either Henrikh Mkhitaryan or Ibrahimovic and Watford were able to scrape it away.
United keeper David De Gea was forced into action early in the second half when Mauro Zarate curled a free kick towards the top corner in what was a rare attempt for the Hornets -- and that spurred United into action as Martial cut back onto his right foot and fired low past Gomes to put the home side firmly in control with an hour gone.