Kei Nishikori became the first man from Japan to reach the US Open semifinals in 96 years, outlasting third-seeded Stan Wawrinka of Switzerland 3-6, 7-5, 7-6 (7), 6-7 (5), 6-4 on Thursday.
The match went 4 hours, 15 minutes, and the 10th-seeded Nishikori managed to shake off any lingering exhaustion from his previous victory, which lasted 4:19 and ended at 2:26 a.m a day earlier.
Nishikori began slowly against the Australian Open champion, but eventually got his bearings and used crisp returns and strong net play to edge ahead.
In Sunday's semifinals, Nishikori will face No. 1 Novak Djokovic or No. 8 Andy Murray, who each owns a US Open title.
The last Japanese semifinalist at the US Open was Ichiya Kumagae in 1918. No man from the country had made it to the final four at any major tournament since Jiri Satoh at Wimbledon in 1933.
Nishikori already was the first Japanese man to be ranked in the ATP's top 10, having climbed to No. 9 in May.
He came into the US Open without a lot of proper preparation, because he was sidelined after having a cyst removed from his right foot in early August.
Nishikori, who is coached by 1989 French Open champion Michael Chang, had never eliminated top-10 opponents in consecutive matches at a major tournament.
The fourth-round marathon win against No. 5 Milos Raonic put Nishikori in his second career Grand Slam quarterfinal; he lost in that round at the 2012 Australian Open.
Wawrinka had won 15 of his last 16 hard-court Grand Slam matches, a stretch that includes a run to his first major semifinal at last year's US Open and his first Grand Slam championship at the Australian Open.
He also had a lot less wear-and-tear on his body over the past 1 1/2 weeks, thanks in part to getting a walkover when the man he was supposed to play in the third round withdrew with an injury.
But in the end, it was Wawrinka who faltered down the stretch, getting broken to close the match when he slapped a forehand into the net.
Nishikori did not really celebrate much, simply looking to the sky as he walked to the net. Chang leaped to his feet and pumped his fists in the stands.
While the 24-year-old Nishikori put on a brave face before facing Wawrinka, saying he expected to be fine, things did not appear to be OK in the early going.
Between points, Nishikori would shake his arms or legs, or flex his hands. During a changeover, he placed a bag of ice on his forehead.
Both men were mostly content to remain anchored near the baseline, swapping booming groundstrokes in lengthy exchanges. And it was Wawrinka who got the better of most of that type of point in the first set, outmuscling Nishikori over and over.
Nishikori got his bearings in the second set, though, coming forward more often. When Wawrinka sailed a backhand long then double-faulted to get broken, it evened the match at a set apiece.
The third set wound up being much more of a struggle than it needed to be for Nishikori, who held a set point at 5-2 but put a forehand into the net.
He then served for the set at 5-3 but got broken in a sloppy game, including one misguided attempt at a between-the-legs shot that found the net and left Chang hanging his head.
Nishikori came within two points of ending the match in the fourth-set tiebreaker, but his two errant groundstrokes sent the match to a fifth.