Everton fought back to claim a 2-1 win over Arsenal as the title hopefuls blew the chance to return to the top of the Premier League standings.
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 half-time and pressing for a winner after the break as Arsenal struggled to generate any sort of rhythm.
With the seconds ticking away, Ashley 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 tomorrow morning (NZ time).
In this morning's other match champions Leicester City failed to continue their mini-revival after a clinical finish by Bournemouth's Marc Pugh condemned them to a 1-0 away defeat in a scrappy clash.
The outcome kept 14th-placed Leicester close to the relegation zone on 16 points, four above the bottom three who play their games in hand tomorrow (NZ time), and was a setback after Sunday's 4-2 home win over fourth-placed Manchester City.
Bournemouth, who kept the visitors on the back foot for much of the contest, grabbed a 34th-minute winner when Pugh swept in a rebound from 13 metres after Leicester keeper Ron-Robert Zieler did well to parry a close range shot by Benik Afobe.
Leicester had missed an early chance in the seventh minute when striker Jamie Vardy, who scored a hat-trick against City, rounded keeper Artur Boruc with a heavy first touch and saw his harmless shot from a tight angle blocked by a defender.
Boruc came to the hosts' rescue in the 90th minute when he blocked a close-range shot by substitute Leonardo Ulloa to help seal the points as Bournemouth moved up to eighth on 21 points.