Chelsea were dealt a big blow to their title hopes as Adam Webster's second-half header earned Brighton & Hove Albion a 1-1 draw at the Amex Stadium.
Brighton started the strongest but fell behind after 28 minutes through Hakim Ziyech's low shot from the edge of the box.
But the hosts grabbed a deserved equaliser on the hour mark when Webster met a corner by Alexis Mac Allister, who had moments earlier been denied by a full-stretch Kepa Arrizabalaga save.
Both sides went in search of a winner but substitute Neal Maupay was unable to turn in Tariq Lamptey's cross before Romelu Lukaku had a shot saved by Robert Sanchez.
Chelsea stay in third place on 44 points, one point behind Liverpool and 12 adrift of Manchester City having played a match more than the leaders.
Brighton extend their unbeaten run to five matches and are ninth with 29 points.
See: Brighton report | Chelsea report
Next fixtures
Brighton: 23 Jan v Leicester (A)
Chelsea: 23 Jan v Spurs (H)
Match officials
Referee: Kevin Friend. Assistants: Simon Beck, Eddie Smart. Fourth official: Simon Hooper. VAR: Andre Marriner. Assistant VAR: Marc Perry.
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