Spain's world number five Rafael Nadal is out of the Cincinnati Masters after losing 6-1 6-3 to Borna Coric.
The Croat, ranked 49th in the world, broke the 14-time Grand Slam champion five times in his third-round victory.
Nadal, 30, received treatment on his left wrist as Coric, 19, won 10 successive games to take the first set and go 4-0 up in the second.
Coric faces the winner of Tomas Berdych and Marin Cilic in his first ATP World Tour Masters 1000 quarter-final.