Arsenal were dealt a hammer blow to their title challenge after being held to a 3-3 draw against West Ham at Upton Park.
The Gunners took an early lead when Mesut Ozil scored on 18 minutes and looked to have wrapped up all three points when Alexis Sanchez doubled the away sides lead.
West Ham boss Slaven Bilic took a gamble starting with Andy Carrol but was rewarded for his belief in the powerful striker.
Carrol scored five minutes before half-time to give the Hammers a glimmer of hope and then went onto equalise just before the interval.
On-loan Fenerbahce striker Emmanuel Emenike came on in the second half as the second striker and put on a hard working display for the Hammers.
The England international striker then went onto score his hat-trick after the break with a powerful header.
Arsenal did manage to equalise thanks to Koscielny but neither side were able to find a winner.
West Ham v Arsenal
Stadium: Upton Park
Kick-Off: 12:45 GMT
West Ham confirmed starting lineup:
Adrian; Tomkins, Reid, Ogbonna, Cresswell; Kouyate, Noble; Antonio, Payet, Lanzini; Sakho
Manager: Slaven Bilic
Arsenal confirmed starting lineup:
Cech; Bellerin, Koscielny, Gabriel, Monreal; Coquelin, Elneny; Sanchez, Ozil, Iwobi; Welbeck
Manager: Arsene Wenger
Goals: Mesut Ozil 18, Sanchez 35, 44, 45, 51, Carroll, Koscielny