Arsenal head coach Mikel Arteta recorded the first victory of his reign with a 2-0 success against Manchester United.
The Gunners took the lead on eight minutes when Sead Kolasinac's cross found Nicolas Pepe, who swept the ball past David De Gea.
Pepe also hit the post before Sokratis doubled their lead three minutes before the break, smashing home after De Gea's parry from a corner.
United had more possession in the second half and substitute Andreas Pereira hit the side-netting before Marcus Rashford fired narrowly over.
But the Gunners held firm to climb to 10th on 27 points. Man Utd remain in fifth spot with 31 points.
See: Arsenal report | Man Utd report
Next fixtures
Arsenal: 11 Jan v Crystal Palace (A)
Man Utd: 11 Jan v Norwich (H)
Referee: Chris Kavanagh. Assistants: Sian Massey-Ellis, Constantine Hatzidakis . Fourth official: Craig Pawson. VAR: Paul Tierney. Assistant VAR: Stephen Child.