Arsenal increased the pressure on Sunderland manager David Moyes with a comfortable victory over a Black Cats side who remain bottom of the table and without a Premier League win this season.
Alexis Sanchez put the Gunners ahead when he got in front of defender Lamine Kone to head in Alex Oxlade-Chamberlain's cross.
The dominant visitors had a strong penalty appeal turned down after Sanchez looked to have been brought down before Jermain Defoe equalised from the spot after keeper Petr Cech had fouled Duncan Watmore.

However, Arsenal reasserted their authority and lead with three goals in six minutes and 20 seconds.
Olivier Giroud came off the bench to guide in a shot and then headed in a Mesut Ozil corner, while Sanchez's close range effort was the signal for the home fans to start streaming out of the Stadium of Light.
The win moved Arsenal top of the Premier League - but whether they stay there depends on how Manchester City and Liverpool fare in their later games.