Maurizio Sarri continued his unbeaten record as Chelsea boss although they were made to work for their victory over BATE Borisov.
The Blues made light work of their opponents a fortnight ago but this was a different story in Belarus.
Olivier Giroud got the only goal of the game as he headed in Emerson's cross but the hosts had chances to level it up - hitting the woodwork three times.
Dmitri Baga had hit the post in the first half from long range and Nikolai Signevich followed sit on the hour mark.
BATE pushed forward for a leveller late on and almost had it in added time when Aleskey Rios beat Kepa, but again the woodwork came to Chelsea's rescue.
The win takes the Blues into the knockout stages with four wins from four.