Unai Emery on Arsenal's top four chances
Pierre-Emerick Aubameyang scored the only goal of the night as the Gunners battled for the slim win against 10-man Watford to go fourth on the table with 66 points.
"Our position in the table is very important," he told Sky Sports "It is in our hands, to take the top four.
"We were working to push the goalkeeper when he wanted to play like he was playing. It's a very good action from Auba.
"I think we can control the match better, and I think it was very important in this position with one player more, to break their lines and to attack the last third better.
"But I think it's very positive to have all three points."
The Gunners, who have a game in hand over fifth-placed Chelsea, host Crystal Palace at the Emirates in their next match.