Olivier Giroud scored his first Chelsea goal in 794 minutes as the Blues progressed to the Europa League knockout stages with a 1-0 win at BATE Borisov.
The France international, who had not scored under Sarri, headed in Emerson’s cross at the near post early in the second period to maintain the Blues’ 100% Group L record.
“I’m pleased for him,” Sarri said. “I know strikers want to score. And so for his confidence, I think it’s very important.
“I don’t want him to be worried about scoring, because for us he’s very important, a very, very useful player for the team.”
Seven changes were made to the side which last Sunday beat Crystal Palace 3-1, with Hazard starting for the first time since the draw with Manchester United on October 20.
Chelsea are now six points clear of Hungarian side MOL Vidi, who moved up to second in the group with a win over PAOK Salonika.