The entire contest was over after just seven minutes when Willian was given the time and space in the box to pick his spot and score with a low finish after receiving the ball from Ross Barkley.
Chelsea's opening Europa League tie could have ended with a much higher scoreline but complacency set in as Alvaro Morata, Pedro and Willian all missed good chances to add to the lead.
Maurizio Sarri opted for a strong team and left Eden Hazard and Mateo Kovacic at home to rest, although he could be tempted to blood in Callum Hudson-Odoi, Ruben Loftus-Cheek and Ethan Ampadu to give the side a fresh look in future ties.
Check out how the Chelsea players did in the gallery below:
