Third-seeded Alexander Zverev has reached the Monte Carlo Masters quarter-finals, where he could meet his brother Mischa, after a tough three-set win over fellow German Jan-Lennard Struff.
Sixth-seeded David Goffin of Belgium has advanced after beating Roberto Bautista Agut of Spain, 6-4 7-5.
Mischa Zverev was to play Richard Gasquet later on Thursday, along with defending champion Rafael Nadal against Karen Khachanov and two-time winner Novak Djokovic facing No.5 Dominic Thiem.
"Hopefully, my brother will win and it will be an amazing day tomorrow," the younger Alexander Zverev said.
He was made to work hard before closing out Struff, 6-4 4-6 6-4.
Zverev was broken to love serving for the match at 5-2 and wasted his first match point when Struff served at 30-40 in the next game.
Struff could have made it even harder for Zverev, but he missed an easy volley at the net at 30-30. Instead of giving him break point, it gave Zverev a second match point. He took it when Struff hit a powerful forehand narrowly wide, and let out a yell of relief.
In the Goffin-Bautista Agut match, the Spaniard dropped serve to trail 4-1.
Bautista Agut cleared a ball from the back of the court just as the ball boy was sprinting across the court. The ball was travelling slowly, bounced and clipped the youngster on the head. Bautista Agut raised a hand up in apology.
Bautista Agut had apparently not seen him, because he was looking down at the ball when he swiped at it.
Serving for the match at 5-2, Goffin wasted two match points, lost the game, then the next two for 5-5.
Goffin, a semi-finalist last year, will play No.4 Grigor Dimitrov or Philipp Kohlschreiber in the last eight.
