The Brazilian stepped up to twice restore the Blues’ advantage, before Diego Costa swooped to put the game beyond doubt late on at Stamford Bridge
Willian’s second-half brace proved decisive as Chelsea twice gave up the lead before eventually seeing off a spirited Stoke City 4-2 in the Premier League on Saturday.
Antonio Conte’s team deservedly led through Gary Cahill’s first-half header, only for Bruno Martins Indi to steer home a scrambled equaliser soon after the break at Stamford Bridge.
Chelsea quickly regained their advantage, Willian benefitting from some great build-up play to make it 2-1 shortly before the hour mark.
Peter Crouch then struck from close range to get it back to 2-2 but the Premier League title favourites refused to give up, Brazil international Willian the man on target again soon afterwards.
Diego Costa, back in the team after serving a one-match ban, then grabbed a late fourth to put the result beyond doubt.
The win saw Chelsea move nine points clear at the top ahead of Liverpool’s clash with Manchester City in Saturday’s late kick-off, while Stoke continue to languish in the bottom half.
Conte’s men also equalled Arsenal’s 2001-02 record for consecutive wins in a single Premier League season, having now notched 13 straight victories under the former Juventus and Italy boss.
The visitors made a strong start to the match, mirroring Chelsea’s 3-4-3 formation to good effect and denying the hosts both time and space.
Nevertheless, it was the league leaders who created the best early chances, as Stoke relied on Lee Grant to keep them on level terms.
Costa struck the goalkeeper’s body with a volley at the back post and was then played in on goal by a pinpoint David Luiz pass from deep, Grant denying the Spain international and then keeping out Eden Hazard’s effort from the rebound.
The keeper, on loan from Derby County, also made a good save to turn away Cahill’s header from a Cesc Fabregas corner.
Stoke failed to heed those warnings, though, allowing Chelsea to break the deadlock in the 34th minute through the same combination. Fabregas swung in a corner from the left and Cahill powered home from close range, this time leaving Grant helpless.
A lapse in concentration allowed the visitors to snatch an equaliser early in the second half, Martins Indi stabbing home the ball after Crouch had put Cahill under heavy pressure from Charlie Adam’s deep free-kick.
Seemingly jolted into life, Chelsea resumed their assault on the Stoke goal and went back in front in the 57th minute.
Victor Moses twisted and turned on the edge of the box and fired off a pass that Hazard stopped dead with one touch, allowing Willian to fire home into the top corner and make it 2-1.
Chelsea’s usual defensive solidity was strangely absent, as Crouch held the ball up, laid it off to Bojan Krkic and then received it back from Mame Biram Diouf to force home another chaotic equaliser seven minutes later.
Mark Hughes and his players were back on level terms for barely two minutes, though, before a Chelsea counter-attack saw Fabregas slip a carefully weighted pass into the path of Willian, who fired home his second and Chelsea’s third from a tight angle.
And any hope Stoke may have had of mounting another comeback were dashed with five minutes to go, Costa bullying Martins Indi off the ball before beating Grant with a fierce strike from another acute angle.
Next up for the Blues is a London derby away to Tottenham on Wednesday, while Stoke are at home to Watford a day earlier.