The first men’s semifinal at the United States Open on Friday had a distinctly warm-up act feel to it. Kevin Anderson and Pablo Carreño Busta do not have Grand Slam titles to their names or worldwide followings.
So the audience in Arthur Ashe Stadium was relatively quiet, and the mood somewhat subdued.
But that did not matter to the emotional Anderson, seeded 28th, who beat No. 12 Carreño Busta, 4-6, 7-5, 6-3, 6-4, to claim a spot in the final.
Most of the tennis world was waiting for what was to follow: the main event, with No. 1 Rafael Nadal playing No. 24 Juan Martín del Potro. Nadal has won two U.S. Opens (2010 and 2013) and 15 Grand Slam titles. Del Potro won the 2009 U.S. Open.
The big-serving Anderson, who is ranked No. 32 on the ATP Tour, became the lowest seed to reach the Open final since the inception of the ranking system in 1973. He is also the lowest-ranked finalist at one of the four majors since Jo-Wilfried Tsonga reached the final of Australian Open in 2008 at No. 38.
Carreño Busta, 26, of Spain, had been the lowest seed remaining in the bottom half of the draw since the fourth round, owing to a combination of withdrawals from injury and upsets. Andy Murray was the No. 2 seed, but he withdrew 48 hours before the tournament because of a sore hip, and No. 4 Alexander Zverev and No. 5 Marin Cilic were taken out before the fourth round.
Several other star players, including Novak Djokovic, Stan Wawrinka, Kei Nishikori and Milos Raonic, did not compete because of injuries, and Anderson and Carreño Busta took advantage.
Carreño Busta, whose best results have come on clay, matriculated through the draw without facing a top-30 player. He also did not drop a set until Anderson rebounded to snatch the second set Friday.
Anderson, 31, was already the first South African to reach a U.S. Open men’s semifinal since Johan Kriek in 1980 (Kriek lost to Bjorn Borg, who then lost to John McEnroe). Kriek was also the last South African finalist in any Grand Slam event; he reached the Australian Open final in 1981. Cliff Drysdale was the last player from South Africa to reach the U.S. Open final, in 1965. He lost to Manuel Santana of Spain.
Anderson, a 6-foot-8 former star at the University of Illinois, had been fiercely defending his serve in his first five matches. In 87 previous service games, he had been broken only three times.
Carreño Busta put a dent in that mystique when he broke Anderson in the first set and carried it to an early win. Anderson committed 14 unforced errors in that first set, compared with only two by Carreño Busta.
But Anderson assumed control of the match in the second set. The last game of the match was the best. Carreño Busta won a tense 38-shot rally on the first point, and yelled as he looked to the sky.
Two points later, Carreño Busta won a 24-stroke rally for 15-30, but Anderson had the good fortune to hit a backhand volley that touched a line, and it came off a ball that was clearly going out. Anderson hit an overhead slam to set up match point and then won it when Carreño Busta hit a forehand into the net.
The newest South African finalist raised his arms, took off his white cap and then climbed into his team box to celebrate in a fashion usually reserved for the championship round.
“I don’t know if a team hug is appropriate before the finals,” Anderson said during an on-court interview with ESPN, “but it seemed like the right thing to do.”
But once it was over, all eyes turned to the two heavyweights coming out on court after them.