Novak Djokovic Getty 2023 Monte Carlo Masters
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Tennis world No. 1 Novak Djokovic was upset by Lorenzo Musetti in the last 16 of the Monte Carlo Masters on Thursday. The veteran was broken eight times before falling 4-6, 7-5, 6-4 to the 21-year-old Italian, who earned the biggest win of his career. 

Djokovic arrived in the competition as the favorite and he took the first set. However, he couldn't rea keep consistent momentum in the wet and windy conditions. The veteran has struggled in Monte Carlo for a while, as he has not gotten past the quarterfinals since 2015.

"(The) feeling is terrible after playing like this, honestly. But congrats to him," Djokovic told the media. "He stayed tough in important moments, and that's it. That's all I can say. Good luck to him."

Musetti entered the match ranked No. 21 in the world. He is now going to his second ATP Masters 1000 quarter-final after playing for two hours, and 54 minutes with a one-hour rain delay. He said the unfavorable weather conditions affected his game and he couldn't find the right balance. Musetti said the rallies at the end were intense, but he was proud of himself for getting through it and pulling off the victory. This was only the second top-5 victory of his career.

"I am struggling not to cry," Musetti said in his on-court interview. "It is an emotional win because it was a really long match. Three-hour match and suspended by rain. It was not easy conditions because it was a little bit windy and cold. Not like we used to play in the recent days. I am really proud of myself and I can see on the screen. I am struggling not to cry because it is a dream for me."

Musetti went on to lose to fellow Italian Jannik Sinner --  the ATP's No. 9 ranked player -- 6-2, 6-2 on Friday. Sinner has now reached his third consecutive Masters 1000 semifinals. He will take on Holger Rune at 9:30 a.m. ET on Saturday.