Martin Odegaard's penalty proved the difference as Arsenal secured a narrow 1-0 win over Crystal Palace, with Mikel Arteta's side holding firm after Takehiro Tomiyasu was sent off in the second half.
Odegaard put the Gunners ahead from the spot with the Norwegian sending Sam Johnstone the wrong way, after the Crystal Palace goalkeeper had brought down Eddie Nketiah in the box.
Arsenal were forced to come through a nervy finale to the match after Tomiyasu was shown a second yellow card for a shirt pull on Jordan Ayew, having earlier been booked for time wasting.