RIO DE JANEIRO -- Rafael Nadal advanced to the semifinals of the Rio Open on Friday without hitting a shot.
The top seed moved on after his quarterfinal opponent, Alexandr Dolgopolov of Ukraine, withdrew before the clay-court match with a shoulder injury.
Tournament organizers said Dolgopolov hurt his shoulder in a doubles match on Thursday.
Nadal's semifinal opponent will be Pablo Cuevas of Uruguay, who defeated Federico Delbonis of Argentina 6-4, 7-6 (4). The match was delayed for 2 1/2 hours with Delbonis leading 4-2 in the second set.
No. 5 Dominic Thiem upset No. 2 David Ferrer 6-3, 6-2. The 22-year-old Austrian won the Buenos Aires title last week -- beating Nadal in the semifinals -- and is the youngest player in the ATP's top 20 rankings.
On the women's side of the ATP-WTA event, Petra Martic of Croatia defeated No. 6 Lara Arruabarrena 6-4, 5-7, 7-5 to reach the semifinals. In another upset, Sorana Cirstea of Romania defeated No. 3 Danka Kovinic 6-1, 6-2 to eliminate the last seeded player from the tournament.