Emile Smith Rowe second-half goal was enough for in-form Arsenal to defeat Watford.
The gunners have extended their unbeaten streak to eight games after the solitary goal by Emile.
Bukayo Saka thought he had given the London side the lead in the 10th minute, but a VAR review ruled the goal offside.
Pierre-Emerick Aubameyang took to the spot to take the penalty, but Ben Foster saved his effort. Foster has now saved ten penalties in his Premier League career.
Smith Rowe Arsenal to Victory
But Claudio Ranieri’s side could not hold their resistance for too long, as Ben White made a mazy run from his half, he evaded a series of challenges from the ‘Hornets’, eventually sliding a pass to Smith Rowe, who placed the ball into the bottom corner.
Substitute Martín Odegaard thought he had doubled their lead, but his initial shot was slotted in by Aubameyang from an offside position.
It became worse for Watford after Juraj Kucka was sent off for a late challenge in the 90th minute.
The lone goal was enough to move Arsenal to 5th on the Premier league table as Watford dropped to 17th, with Arsenal extending their head to head record against Watford, winning the last four meetings.