The result though did not reflect the match as the hosts should have comfortably won the game with the amount of clear cut chances they created.
Having won their last two in the Premier League and picked up a valuable draw against in midweek against Atletico Madrid in the Champions League, the Red Devils appeared to have finally picked up some form under Ralf Rangnick.
However, against Roy Hodgson's side, they were made to pay for not making the most of their dominance.
Particularly in the opening exchanges when Cristiano Ronaldo, who had a goal disallowed, should have made the visitors pay.
After receiving a cut-back from Aaron Wan-Bissaka, the Portugal captain could only strike the left side of the post with Ben Foster appearing to look beaten.
Bruno Fernandes was also guilty of two big misses in the first-half, the first after Anthony Elanga played him through, and the second when Paul Pogba produced an exquisite ball over the top only for the captain on the day to send his shot wide.
Ronaldo spurned another couple of glorious opportunities after the break.
Even after Ralf Rangnick made substitutions in the second half when he played an attack that contained Pogba, Fernandes, Sancho, Rashford, Elanga and Ronaldo, the hosts could not put the ball into the net.
For Watford though, it's a superb result in their battle to avoid relegation.
Whilst that draw doesn't lift them out of the bottom three, it's another point on the board for Hodgson's men who have gone to one of the toughest grounds in the league and taken a result.
In picking up the result, they had Ben Foster to thank who showed every bit of his experience in goal.
Aged 38 years and 329 days, the former Man United goalkeeper became the oldest visiting goalkeeper to keep a clean sheet at Old Trafford in the Premier League, OptaJoe reported.
What makes the stat even more impressive is that it had been held for nearly 20 years when David Seaman, aged 38 years and 231 days, did the same for Arsenal in May 2002.
It's a brilliant result for Watford who could be looking back on this result if they avoid relegation this season.
For Man United though, it could be a damaging one as they are now only two points clear of fifth placed Arsenal, who have three games in hand.
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