The Belgium international was left out of his side's travelling party to face PAOK in the Europa League, with Sarri claiming that Hazard had complained of tiredness ahead of the match.
Hazard returned to the starting lineup for Sunday's goalless draw with West Ham United and, while he was unable to help extend the team's perfect start to the season, he insists that he is still feeling fresh after a World Cup summer.
"I feel 200%! [Sunday] was hard; I missed a couple of passes, dribbles but I feel good. Confidence is up so I hope we can keep up our momentum to win games," he told Sky Sports News.
"We knew it was a difficult place to come and win. You can try and play behind the lines - and with the quality we have we should do better - but it's hard when they have men behind the ball.
"We could have won because we missed a lot of chances but we also could have lost because they missed a lot of chances. We're not happy with the draw because we just want to win games but when you see the chances they've had, I think we can be happy. A draw is a fair result."
Chelsea's next match sees them take on league leaders Liverpool, who are yet to drop a point this season.