Borna Coric produced a stunning straight-sets upset of Rafael Nadal on Thursday to reach the quarterfinals of the Western & Southern Open at Mason, Ohio.
The 19-year-old from Croatia delivered a 6-1, 6-3 victory over the third-seeded Nadal at the Cincinnati-area tournament.
Coric had dropped 10 consecutive matches against Top 10 competition before controlling play against Nadal.
Nadal experienced issues with his left wrist and left elbow and received treatment after losing the first set. He was unable to mount an ineffective charge in the second set as he dropped the first four games.
Nadal committed 27 unforced errors and five double faults in the sub-standard effort.
Dimitrov needed just 83 minutes to post his fourth consecutive victory over Wawrinka.
Dmitirov next faces American Steve Johnson in a battle of unseeded players. Johnson posted a 6-3, 7-6 (6) victory over France's Jo-Wilfried Tsonga.