Defending champion Carlos Alcaraz cruised past Alexander Zverev to reach the Madrid Open quarter-finals but Daniil Medvedev fell to a shock defeat.
Top seed Alcaraz dominated throughout against Zverev, who he defeated in last year's final, in a 6-1 6-2 victory.
The 19-year-old Spaniard will face Karen Khachanov in the last eight after he beat fifth seed Andrey Rublev.
Medvedev, seeded second, complained about the crowd in a 7-6 (7-1) 6-4 loss to fellow Russian Aslan Karatsev.
The world number three returned to his chair because of booing from the crowd during the first-set tie-break before the chair umpire was able to encourage him to return to the court.