NEW YORK -- For one set Thursday, Marin Cilic frolicked on the Arthur Ashe Stadium court. He hit crazy, curving backhands and had sixth-seeded Juan Martin del Potro muttering under his breath.
But there was a second set. It was then that del Potro found his game on a gloomy afternoon where the wind played tricks with the ball. Del Potro did too, moving Cilic from side to side. By the end, Cilic was left slapping aimless volleys into the net and making useless challenges to balls well wide.
The sixth-seeded del Potro, a 20-year-old from Argentina, made it to his second major tournament semifinal with his 4-6, 6-3, 6-2, 6-1 victory over the 16th-seeded Croatian Cilic, who is also 20.
In Saturday's semifinals, del Potro will play the winner of Thursday night's quarterfinal between third-seeded Rafael Nadal and 11th-seeded Fernando Gonzalez of Chile. The top seed, five-time defending champion Roger Federer, and fourth-seeded Novak Djokovic will be in the other semifinal.
The Nadal-Gonzalez match was stopped twice because of rain. Nadal was ahead 7-6 (4), 2-2, when the first rain delay began; play resumed 1 hour, 16 minutes later at 9:44. The second time, the score was 7-6, 6-6 and 3-2 in the tiebreak. Nadal had called for the trainer after he won the first set and seemed to complain of pain in his abdominal muscle area, the same area where he was treated earlier in the tournament.
In his match with del Potro, Cilic was the aggressor. But del Potro, a French Open semifinalist this year, said: "I was thinking to make every point the same, to put the ball on the court. When you are going to fight until the end, you will have many chances."
Before the men's match, Venus and Serena Williams had roused the modest morning crowd by winning their semifinals doubles match, 7-6 (4), 3-6, 6-2, over a Russian team of Alisa Kleybanova and Ekaterina Makarova. It was a spirited workout for Serena, the defending singles champion, who will play the first women's semifinal today, beginning at 12:30 p.m. against unseeded Kim Clijsters. Venus and Serena have also won the Australian Open and Wimbledon doubles titles this year.
The second semifinal will be between a pair of 19-year-olds: ninth-seeded Caroline Wozniacki of Denmark and unseeded Belgian Yanina Wickmayer.
Today's featured matches
AT ARTHUR ASHE STADIUM
Beginning at 12:30 p.m.: : Second-seeded Serena Williams against Kim Clijsters of Belgium, women's singles semifinals; Yanina Wickmayer of Belgium against ninth-seeded Caroline Wozniacki of Denmark in women's singles semifinals; fourth-seeded Lukas Dlouhy of the Czech Republic and Leander Paes of India against third-seeded Mahesh Bhupathi of India and Mark Knowles of the Bahamas, men's doubles final.
