A second-half brace from Aaron Ramsey saw Arsenal to a third straight Premier League win away at Sunderland in controversial circumstances.
Olivier Giroud put the Gunners ahead after 10 minutes after meeting a cross from Mesut Ozil, but Modibo Diakite almost levelled instantly when he headed against the bar.
As the first half progressed, Arsenal looked more composed and dominated possession with Ozil linking well with Jack Wilshere.
However, Sunderland managed an equaliser just after the interval when Adam Johnson was fouled by Laurent Koscielny and Craig Gardner sent Wojciech Szczesny the wrong way.
Ramsey put the visitors back in front midway through the second half, volleying home past Keiron Westwood.
But the Black Cats may feel aggrieved not to have had a second goal when Jozy Altidore appeared to have scored, but referee Martin Atkinson pulled play for the foul on the American instead of playing the advantage. Replays show the ball to have crossed the line despite Koscielny's effort to clear.
Ramsey made sure of the three points minutes later and the result means that Arsenal secure a fifth straight victory in all competitions, while Sunderland are bottom of the Premier League without a win.
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