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.Thiem will face Guido Pella of Argentina in the semis. He defeated Daniel Gimeno-Traver of Spain 5-7, 6-1, 7-5, but Thiem will be a strong favorite to reach the final.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.