SANTIAGO, Chile — Top-seeded home favourite Christian Garín retired from his Chile Open quarterfinal because of back pain after losing the first set of his quarterfinal match against Brazil's Thiago Wild.

Wild led 7-6 (1) when Garín retired. Wild will face Argentina's Renzo Olivo in the semifinals. Olivo beat sixth- seeded Hugo Dellien of Bolivia 3-6, 7-6 (5), 7-5 in the clay-court event.

Garín, the Rio Open winner Sunday, left the court looking upset after one hour of play as local fans clapped.

The Chilean had also struggled with back pain in his round-of-16 win against Spain's Alejandro Davidovich Fokina.

Norway's Casper Ruud and Spain's Albert Ramos Vinolas will meet in the other semifinal.

The second-seeded Ruud topped Federico Delbonis of Argentina 7-5, 7-5, and the third-seeded Vinolas eliminated Brazilian Thiago Monteiro 6-4, 6-4. ___

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