Chelsea crashed to a shock 3-2 defeat at West Ham as Arthur Masuaku’s fortuitous late winner capped the Premier League leaders’ second half collapse in a dramatic London derby on Saturday.
Thomas Tuchel’s side went ahead through Thiago Silva but Manuel Lanzini’s penalty drew West Ham level.
Mason Mount restored Chelsea’s advantage just before half-time, only for Jarrod Bowen to blast West Ham’s second equaliser soon after the interval.
Chelsea dominated for long periods but made too many mistakes at both ends and paid the price with three minutes left as Masuaku’s miscued cross somehow found its way past Edouard Mendy.
It was the Blues’ first defeat in their last 13 games in all competitions and their spell at the top of the Premier League might be over by Saturday evening.
They are just one point ahead of second placed Manchester City, who visit Watford later on Saturday, with third placed Liverpool also able to go above Chelsea if they win at Wolves.
Fourth placed West Ham once again showed their ability to make life uncomfortable for the big guns.