Daniil Medvedev was again drawn into a heated exchange with an umpire before crashing out of the Monte Carlo Masters in a 6-3 7-5 defeat by Karen Khachanov in the last 16 on Thursday, while Novak Djokovic and Jannik Sinner advanced to the quarter-finals.

Fourth seed Medvedev, who had reached at least the quarter-finals in his last two appearances at Monte Carlo, never truly got going against fellow-Russian Khachanov. After a topsy-turvy start with four breaks in the first four games, Medvedev double-faulted to gift Khachanov the lead at 5-3, with the world number 17 holding serve comfortably to clinch the opening set. Medvedev shook off some of his early rustiness in the second and had set point when he was 5-4 up, but squandered that opportunity and was unable to break Khachanov's serve.

Khachanov's hold under pressure proved the final straw for Medvedev, who faded quickly and hurled his racket against the backboard after an erroneous call from a line judge. "Open your freaking eyes," Medvedev, who also argued with the chair umpire after his win over Gael Monfils on Wednesday, shouted at the umpire and supervisor, before being issued a point penalty.

Khachanov reached the last eight in Monte Carlo for the first time. "Mentally, even though I've lost a few hard matches to him on hard courts, I know he doesn't like to play on clay and that gives me some extra confidence," Khachanov said in his on-court interview. "Sometimes I know Daniil can lose his mind. Sometimes he uses it as a tool, but it can get out of control sometimes. I tried not to look at him or focus on him, and just serve it out." World number one Djokovic looked in trouble early on, but rallied to win 7-5 6-3 against Lorenzo Musetti, the player who knocked the Serb out at this stage in last year's tournament.

The Italian broke in the opening game before Djokovic bounced back with two breaks to take the first set. The pair traded breaks twice in the second set, but Djokovic broke a third time to make it 5-3 and held serve to advance. "He was the better player for those first seven games, played some great tennis," Djokovic said. "But this is clay and obviously things can turn around very quickly and a break of serve is not as big advantage on this surface compared to the other surfaces."

Djokovic, twice Monte Carlo champion, has not advanced beyond the quarter-final stage since he won in 2015, and will face 11th seed Alex de Minaur who beat Alexei Popyrin 6-3 6-4 in an all-Australian clash. Australian Open champion Jannik Sinner had little trouble in defeating Jan-Lennard Struff 6-4 6-2, despite the German breaking serve in the opening set. "I broke him quite early and then he broke me back," Sinner said. "I knew it was going to be really tough but I guess I returned really well, especially on second serves. I can be very happy."

Sinner will next face seventh seed Holger Rune in a rematch of last-year's semi-final, which was won by the Dane. Rune finished off his rain-delayed clash against Sumit Nagal with a 6-3 3-6 6-2 win, before returning to court to see off Grigor Dimitrov 7-6(9) 3-6 7-6(2) in a three-and-a-half-hour thriller. "It was a great match. It was tough physically. I had a match earlier today which was two sets, so I played five sets today actually, which is pretty brutal," Rune said.

Twice Monte Carlo champion Stefanos Tsitsipas defied a spirited comeback from fifth seed Alexander Zverev to win 7-5 7-6(3). The Greek 12th seed took a 5-0 lead in the second set before the German made an impressive recovery. Tsitsipas, winner in 2021 and 2022, held his nerve in the tiebreak to reach the quarter-finals where he will meet Khachanov. Norwegian eighth seed Casper Ruud also reached the last eight after beating Hubert Hurkacz 6-4 6-2 and will meet 14th seed Ugo Humbert.