Andrey Rublev says his behaviour in his third-round French Open loss - where he slammed a racquet on court and on his knee - was the worst it has been at a Grand Slam.

The sixth seed lost 7-6 (8-6) 6-2 6-4 against world number 35 Matteo Arnaldi of Italy.

Rublev showed signs of agitation at the end of the first set and was warned by the umpire after throwing his racquet to the clay.

The Russian shouted at his team after being broken in the second set and bounced his racquet on the court between Arnaldi serves, drawing ironic cheers from the crowd.

The 26-year-old also hit his knee with his racquet in the third set after kicking his chair on several occasions.

"Completely disappointed with myself with the way I behaved, the way I performed, and I don't remember behaving worse in a slam ever," Rublev said.

"I think it was the first time I have ever behaved that badly."

Rublev is a 10-time Grand Slam quarter-finalist but has never gone beyond that stage.

He was defaulted in Dubai for unsportsmanlike conduct three months ago but made a conscious effort to control his on-court demeanour, external on his way to the Madrid Open title in May.

"I feel in some moments it is tough to be kind to myself," he said.

"Of course if I was able, I'm sure that those moments will never happen."

Arnaldi will face ninth seed Stefanos Tsitsipas of Greece next.