Premier League leaders Arsenal extended their lead at the top of the table to five points, but could only manage a 1-1 draw against a 10-man Chelsea side at Stamford Bridge on Sunday.
Chelsea's Moises Caicedo was sent off in the first half for a dangerous challenge on Mikel Merino.
Despite the numerical advantage, Arsenal conceded first to a Trevoh Chalobah header, before Merino salvaged a point for the Gunners.
Manager Mikel Arteta admitted his side "lacked certain detail" in the attack after the sending-off, allowing Chelsea to defend resolutely and earn a gritty point.
