Diego Costa sparked the turnaround for Chelsea, cancelling out a 45th-minute own goal by teammate Gary Cahill with an equaliser in the 60th after chesting down Cesc Fabregas’ long ball. Costa set up substitute Willian to put Chelsea ahead in the 70th and Eden Hazard added a third in the 90th, before Ag¸ero’s tackle on Luiz sparked the late skirmishes. Other results: West Ham 1 Arsenal 5; Sunderland 2 Leicester 1; Stoke 2 Burnley 0; Tottenham 5 Swansea 0; West Brom 3 Watford 1; Crystal Palace 3 Southampton 0. TURNAROUND A crushing defeat was about to be confirmed for Manchester City when Sergio Ag¸ero flew into a knee-high challenge and Fernandinho grabbed a goading opponent by the throat in an ensuing melee, shoving him over an advertising hoarding. City’s players didn’t just lose a match to a big title rival. They lost their heads. In a feisty, action-packed game between two of the Premier League’s heavyweights, Chelsea scored three goals in the final half-hour and rallied for a 3-1 win at City yesterday. It was an eighth straight victory for the leaders, all of them coming since their coach, Antonio Conte, switched to a 3-4-3 formation that is making the team irresistible going forward. City dropped four points behind Chelsea in fourth place. Ag¸ero and Fernandinho, two mainstays of Pep Guardiola’s City team, were both red-carded in those unedifying final seconds that saw tempers flare and both sets of players pushing and shoving on the field. Ag¸ero is set to miss the next four matches for his lunge on David Luiz, because it was his second sending-off this season.