<p>Italian 11th seed Jannik Sinner retired injured from his fourth-round French Open clash against Russian Andrey Rublev after a good start to the match on Monday.</p>.<p>The 20-year-old, bidding to make his second quarter-final in Paris after 2020, won the opening set 6-1 before getting treatment on his left knee in the second, which he lost 6-4.</p>.<p>Rublev, the seventh seed, was 2-0 up in the third when Sinner threw in the towel.</p>.<p>"I felt good or quite ok in the first set and after serving at 2-1 (in the second) I felt something from that point," Sinner said.</p>.<p>Sinner had also been treated in the previous round but said the pain was in a different place on Monday.</p>.<p>"I felt it too much. I was hoping it would go away. It didn't, so playing like this, unfortunately, was not the right thing to do," a visibly disappointed Sinner told a news conference.</p>.<p>He said he would undergo tests in the coming days to determine the exact cause of the problem and was not clear about how the rest of the season would shape up for him.</p>.<p>The grasscourt season is kicking off after the end of the French Open with Wimbledon starting in a month's time.</p>.<p>"I will have to see what it means," he said. "What could have caused it."</p>.<p>In the quarter-finals, Rublev will face either Croatian Marin Cilic or second seed Daniil Medvedev of Russia.</p>
<p>Italian 11th seed Jannik Sinner retired injured from his fourth-round French Open clash against Russian Andrey Rublev after a good start to the match on Monday.</p>.<p>The 20-year-old, bidding to make his second quarter-final in Paris after 2020, won the opening set 6-1 before getting treatment on his left knee in the second, which he lost 6-4.</p>.<p>Rublev, the seventh seed, was 2-0 up in the third when Sinner threw in the towel.</p>.<p>"I felt good or quite ok in the first set and after serving at 2-1 (in the second) I felt something from that point," Sinner said.</p>.<p>Sinner had also been treated in the previous round but said the pain was in a different place on Monday.</p>.<p>"I felt it too much. I was hoping it would go away. It didn't, so playing like this, unfortunately, was not the right thing to do," a visibly disappointed Sinner told a news conference.</p>.<p>He said he would undergo tests in the coming days to determine the exact cause of the problem and was not clear about how the rest of the season would shape up for him.</p>.<p>The grasscourt season is kicking off after the end of the French Open with Wimbledon starting in a month's time.</p>.<p>"I will have to see what it means," he said. "What could have caused it."</p>.<p>In the quarter-finals, Rublev will face either Croatian Marin Cilic or second seed Daniil Medvedev of Russia.</p>