"It was an open game but in Milan we moved the ball very quickly and again today but we lacked a bit of freshness today".
Though he holds legendary status, he is also held in high regard as a coach, with Premier League stars Eden Hazard, Romelu Lukaku and Kevin De Bruyne all said to be impressed with his abilities.
The hosts had to wait until just shy of the hour mark to double their advantage, with Mkhitaryan playing a defence-splitting throughball for Aubameyang to round Karnezis and slot home.
Arsenal, who had lost eight of their previous 14 matches in all competitions, remain in sixth place in the standings.
The victory over Watford does however mean the Gunners have won two on the bounce, having ended a four-game losing run with the 2-0 win over Milan at the San Siro on Thursday. But I wanted absolutely to win this game and it was hard, but overall, it gets us a little bit out of that negative spiral that we were in. "We dealt well with set pieces which is why they could not come back". For all of the recent turbulence of the club that many attribute to the stubbornness of Wenger, to win 700 games for one club is an astounding achievement that should be praised. We had a nightmare week, so overall we still have some work to do.
The Czech goalkeeper had not kept out a spot-kick in the top flight since denying Clint Dempsey in the final minute of a goalless draw between Chelsea and Fulham at Craven Cottage seven years ago.
Arsenal then slowed down the game's tempo by keeping possession in their own half. They attacked well in the first half, and an eager Ozil looked frustrated at times as he failed to make anything of a couple of decent chances, at times hindered by the quality of passing from his team-mates.
Cech - who has not saved a penalty in the Premier League since 2011 - stopped the shot to his right.
Alex Iwobi: Impressed with his hold-up play during the game, but was disappointing with his crossing once more.