The midfielder then sealed the points for his side on 72 minutes with a powerful finish into the bottom corner.
Here, Sports Mole takes a closer look at the action between the two teams in North London.
On target: 6
On target: 2
Was the result fair?
Arsenal struggled to break Palace down during the first half, but it was a different story after the break as they showed a more clinical edge in front of goal to claim a deserved victory.
The Gunners huffed and puffed in the first half to no avail as Palace's robust midfield and defence proved difficult to get through. The passing was very neat and nice from the hosts, but it was all rather ineffective - a familiar story. However, they had an added sharpness to them in the second half and were duly rewarded with two goals. Arsene Wenger's side will need to dispatch of teams like Palace if they want to keep their title challenge on track, and they did on this occasion without a great deal of hassle.
Manager Tony Pulis will be pleased with the effort and commitment that his players showed as they frustrated Arsenal for much of the first half. Not only that, but they were also brave going forward and had their hosts worried through the attacking trio of Marouane Chamakh, Cameron Jerome and Jason Puncheon. That said, it looked difficult for Palace to fight back once they went behind. They continued to give it a go against the craft and guile of the Gunners, but it proved to be a bridge too far in the end.
Sports Mole's man of the match
Alex Oxlade-Chamberlain: The Arsenal midfielder stole the show with his two goals and provided the home side with plenty of energy and dynamism throughout.
Palace nearly bagged themselves an instant equaliser after going behind, only for Marouane Chamakh's poor header to be kept out by Wojciech Szczesny. The forward had the whole goal to aim for, but somehow he planted his effort right into the path of the goalkeeper.
Jon Moss gave a competent display out in the middle, allowing both teams to play a flowing, entertaining match. In contrast to Arsenal's flair, Palace often adopted a physical approach, but he did not penalise either side unnecessarily too often.
Arsenal: The Gunners return to Premier League action on Saturday when they travel to Anfield to face Liverpool.
Palace: The Eagles continue their battle for Premier League survival on Saturday as fellow strugglers West Bromwich Albion visit Selhurst Park.