Marko Arnautovic exchanged passes with Manuel Lanzini before wrong-footing Cesar Azpilicueta and placing the ball beyond Thibaut Courtois with his left foot.
Manchester United F.C. manager Louis van Gaal stormed out of his pre-match press conference on Wednesday due to the speculation about his position, but he dismissed the suggestion that the pressure was getting to him.
Pre-match media reports suggested Manchester United F.C. manager Louis van Gaal was one defeat away from the sack and the 64-year-old Dutchman saw his team's run of games without a win extended to seven at a windswept Britannia Stadium.
Manchester City F.C. suffered a serious blow to their Premier League title hopes after they were beaten 2-0 by Stoke City.
Marko Arnautovic stunning strike hand Chelsea third straight defeat, their seventh in total, and left them in 16th place in the table.