* Ashley Williams' header gave Everton a 2-1 victory over Arsenal
* Alexis Sanchez put Arsenal ahead with a deflected free kick
* Seamus Coleman equalised just before halftime with a header
* Williams nodded his first goal for the club to snatch victory
* Arsenal visit Manchester City next, Everton host Liverpool
Dec 13 (Reuters) - Ashley Williams powered home a towering header in the 86th minute as Everton fought back to claim a 2-1 win over Arsenal as the title hopefuls blew the chance to return to the Premier League summit on Tuesday.
It looked like business as usual for the visitors, who have been scoring freely in recent weeks, when Alexis Sanchez netted his 12th league goal of the season with a deflected free kick after 20 minutes.
Everton though warmed to the task, levelling through Seamus Coleman's header a minute before halftime and pressing for a winner after the break as Arsenal struggled to generate any sort of rhythm.
With the seconds ticking away, Williams rose high above the defence to head Ross Barkley's hanging corner into the net for his first Everton goal to leave Arsenal three points adrift of leaders Chelsea who visit Sunderland on Wednesday. (Reporting by Toby Davis; Editing by Tony Jimenez)