Sarri says he expected a difficult test against Slavia but was pleased to see Chelsea show their character by staying in the game and then getting a crucial away goal.
“I think we knew very well that it would be really very difficult,” he tells a post-match news conference.
“The opponents are very physical, very aggressive and so we knew we had to face difficulties during the match. We were able to front up and face them well and then, in the second half, we were able to play better.
“We need to think the second leg will be difficult, too, because these opponents are dangerous away – like in the round against Genk. We need to be careful.
“I am happy with the result and also the performance because, at this moment, we were able to suffer [and come through]. In the past, we weren’t able to suffer in difficult moments.
“This is not for the first time but in the past, when we were in trouble, we conceded immediately. Now we can fight and suffer without conceding. That’s a step forward.”
Starman, Eden Hazard started on the bench, while Callum Hudson-Odoi was left out completely, with Sarri suggesting the teenager needed a rest.
On Hazard, the coach says: “I wanted him on the bench because I thought this match would be difficult and I would probably need to use him. If we were 1-0 [up] at half-time, I wouldn’t have used him.”