NEW YORK — The men's Big Four came to the U.S. Open minus Rafael Nadal, and for stretches of Saturday afternoon, it looked as though the three present might be reduced to two.
No. 3 seed Andy Murray was made to work harder than he did at any point in his Olympic gold medal run in London, needing almost four hours in sweltering weather to survive 30th-seeded Feliciano Lopez 7-6 (7-5), 7-6 (7-5), 4-6, 7-6 (7-4).
Murray struggled with his consistency off the ground, making an uncharacteristic 16 unforced errors with his forehand and 24 with his backhand.
Lopez won eight more points than Murray (162 to 154) and had a better winner-to-unforced error differential (plus-13 to plus-5), but ultimately he was undone by costly unforced errors in the crucial stages of the tiebreaks.
Murray, who prides himself on his fitness, did not seem affected by the humidity or temperature that lingered in the low 90s, though he said he was.
"I always say you never take matches or any players for granted," he said, "because on any given day, you know, things can change. If you don't play your best, they play a great match, you know, you can lose. Sometimes you just have to find a way to get through. I did that (Saturday).
"I hope it's a benefit, if anything," Murray said of the third-round trial. "I need to spend time on the court. I need to go through tough moments, tough situations."
In the round of 16 he faces Milos Raonic, seeded 15th, who beat Tampa resident James Blake 6-3, 6-0, 7-6.
Top seed Roger Federer, who looks on course to play Murray in the semifinals, had a considerably easier match, beating No. 25 seed Fernando Verdasco, 6-3, 6-4, 6-4, in just more than two hours.
"(Federer) didn't give me many chances with his serve," said Verdasco, who held only one break point and failed to convert it.
Serena Williams exacted some revenge with a 6-4, 6-0 win over Ekaterina Makarova, who had upset an injured Williams 6-2, 6-3 in the fourth round of the Australian Open in January.
"Definitely was motivated," Williams said. "Knowing that I lost, could definitely happen again. Did not want that to happen."
Second seed Agnieszka Radwanska dealt with the heat and former No. 1 Jelena Jankovic with equal aplomb during a 6-3, 7-5 victory.
"I was feeling like I was melting there," Radwanska said. "I survived the match."
clijsters done: Four-time Grand Slam singles champion Kim Clijsters' career ended when she and Bob Bryan lost their second-round mixed doubles match to Ekaterina Makarova and Bruno Soares 6-2, 3-6, 12-10. Clijsters, who lost in the second round of singles and the first of women's doubles last week, has said she would retire after the U.S. Open.