STOKE-ON-TRENT: Gary Cahill kept Chelsea’s title charge on track as the defender’s 87th-minute winner gave the Premier League leaders a hard-fought 2-1 victory at Stoke on Saturday. Willian’s cheeky free-kick put Chelsea ahead in the 13th minute but Stoke equalised when Jonathan Walters converted a penalty conceded by Cahill seven minutes before half-time. Chelsea looked the more likely winners after the break, as Marcos Alonso’s free kick hit the crossbar and goalkeeper Lee Grant superbly denied Pedro. Stoke were never out of the game but Cahill fired home to punish a mistake by Erik Pieters, who failed to clear David Luiz’s header from a corner. Victory for Chelsea made it 12 games unbeaten in all competitions and they are now 13 points clear of second-placed Tottenham, who face Southampton on Sunday. Stoke’s defeat ended their eight-match unbeaten home record going back to a 1-0 defeat to Bournemouth on November 19. Chelsea were without Eden Hazard after the Belgium international injured a leg muscle in training and Pedro’s recall in his place was the only change to the side that beat Manchester United 1-0 in the FA Cup quarter-finals on Monday. There was no place in the 18 for John Terry, who Stoke boss Mark Hughes admitted enquiring about the last time the clubs met on New Year’s Eve, following a minor injury.