The umpire was forced to step in when Novak Djokovic screamed “shut the f*** up” at a spectator during his Monte Carlo loss to Casper Ruud. A member of the crowd shouted during a rally that Djokovic lost, prompting a reaction from the world No. 1. Chair official Mohamed Lahyani backed Djokovic, telling the fans off for disturbing him.

Djokovic suffered his fourth loss of the season on Saturday, crashing out in the semi-final of the Monte-Carlo Masters. The 36-year-old mounted a comeback after going down an early break in the final set but Ruud still managed to come through 6-4 1-6 6-4.

After getting back on serve at 3-4 in the third set, the top seed was provoked by someone in the crowd. He lost a 15-shot rally by sending the ball wide, with a spectator shouting “out”. Djokovic immediately turned around and screamed “shut the f*** up” in response, continuing to rant as he glared at the person in question.

As he went to towel down and prepare to serve again, the umpire quickly interjected and reminded the crowd not to get involved in points. “Please don’t make any call during the rally. Monsieur, merci,” Lahyani said, giving the spectator a thumbs up.

“Apologies for the language but he was clearly disturbed,” Nick Lester said on commentary. Djokovic went on to hold serve but it was the last game that he won as Ruud held and then broke to clinch victory.

There appeared to be more issues with the crowd in the final game of the match, which saw Djokovic go 0-40 down. He saved the first two match points before giving it away on a double fault. In his post-match press conference, the top seed was asked whether he was affected by booing when a man was expelled at the beginning of the game.

But Djokovic was none the wiser and gave a short, snappy response. “I don’t know. No, I was not. I didn’t even see what’s happening,” he said.