Chelsea manager Thomas Tuchel suffered the first defeat of his reign as lowly West Bromwich Albion swept to a stunning 5-2 win, while runaway Premier League leaders Manchester City prepared for a tough test at Leicester on Saturday.
Tuchel saw his 14-game unbeaten run since replacing the sacked Frank Lampard come to juddering halt at Stamford Bridge.
Christian Pulisic gave Chelsea the lead in the first half, but Blues defender Thiago Silva was sent off two minutes later for a second booking.
Second-bottom West Brom made the most of that gift in first-half stoppage-time as Matheus Pereira struck twice in quick succession.
They were the first home league goals conceded by Chelsea since Tuchel arrived in January, also ending a run of seven successive clean-sheets in all competitions.
Mason Mount’s reply was no consolation for Chelsea, who conceded five at home in the league for the first time since 2011 when Robinson grabbed his second in the final moments.
Chelsea remain in fourth place after their first home league defeat against West Brom since 1978.
But West Ham and Tottenham would both go above them if they win their games on Monday and Sunday respectively.
It was the worst possible preparation for Chelsea’s Champions League quarterfinal first leg against Porto on Wednesday.
Tuchel called for calm, insisting he would not read the riot act to his players and taking his share of the blame.