NEW YORK, NY - SEPTEMBER 06: Juan Martin del Potro (R) of Argentina shakes hands with Roger Federer (L) of Switzerland after their Men's Singles Quarterfinal match on Day Ten of the 2017 US Open at the USTA Billie Jean King National Tennis Center on September 6, 2017 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Abbie Parr/Getty Images)

As if it's etched in some old stone buried in Flushing Meadows Park that Roger Federer and Rafael Nadal shall never meet at a U.S. Open, Federer and Nadal will not meet at this U.S. Open. The semifinal that loomed in the air through the two weeks here fizzled one match from fruition, and it did so via a familiar, beloved "villain."

Juan Martin del Potro, the Argentine 2009 U.S. Open champion who prevented a Federer-Nadal meeting when he ousted Nadal in a 2009 semifinal, spent Wednesday night in Arthur Ashe Stadium reminding a stirred-up crowd of his sublime quality. As his stemwinder of a fourth-round win Monday somehow had failed to sap his energy, del Potro marshaled his barbarous serve, his peerless forehand, his shored-up backhand and his thick grit to remove Federer, 7-5, 3-6, 7-6 (10-8), 6-4, and to treat Federer to a second crushing U.S. Open loss, eight years after the first in a five-set final. If the illness del Potro carried through Monday night had persisted, then it appeared everyone should want such illness.

"Juan Martin fought like a lion," Federer said.

"Tonight I played just free," del Potro said.

It meant that while Federer and Nadal have played four times at the Australian Open, five times at the French Open and three times at Wimbledon, they remain peculiarly on zero here. That's true even though the top-ranked Nadal briskly went to the semifinals on Wednesday afternoon, tearing through 53rd-ranked 19-year-old Andrey Rublev of Russia, 6-1, 6-2, 6-2, in 96 minutes, after which Nadal answered a big batch of questions about playing Federer, understandable for the hope, while Rublev said, "I'm really happy" just for the experience, understandable for his age.

Del Potro, who spent a three-year chunk of this decade wondering whether his fractious wrists would allow him back to the upper crust, wanted no such happiness and held his resolve particularly in a third-set tiebreaker on which the match turned.

In that 18-point ruckus, Federer held four set points: at 6-4, 6-5, 7-6 and 8-7. Del Potro contributed some blunders but then contributed the fine amnesia necessary to negate those blunders. In his four predicaments he produced a fine low forehand return, a 124-mph service winner, a low shot that confounded Federer at the net (so that he lifted it long) and a commanding service point when he whacked away a convenient return.

When he sent another low ball to Federer at the net while returning up 9-8, and Federer directed it upward and long, both Federer and Federer-Nadal looked imperiled. Asked if he was pining too much for the daydream match for Friday, replied, "I wasn't. You were."

In five service games in the fourth set, del Potro won 20 of 23 points. That dominance fueled Federer's edginess and made it glaring at 2-2 when he slammed an overhead into the net on deuce and suffered del Potro's masterful, cross-court, winning backhand return on break point. Then, at 30-30 in the final game, Federer took an open volley and, with shocking unease for the 19-time Grand Slam champion, directed it so long and wide it might have caromed through the stadium hallways.

Within moments, Nadal would have a match with del Potro while Federer, who strained through two five-set matches here, would have a clear look in the mirror. "Of course it is a pity but, you know, Juan Martin deserves it more," he said. "I feel I have no place in the semis and he will have a better chance to beat Rafa, to be honest. The way I played or am playing right now, it's not good enough in my opinion to win this tournament. It's better I'm out and somebody else gets a chance to do better than me."

One last destroyed tennis ball from a del Potro forehand, his most renowned shot, into an open court after a ringing serve, and the motley U.S. Open had a final four of No. 1 Nadal, No. 28 del Potro and two first-time Grand Slam semifinalists, No. 19 Pablo Carreno Busta and No. 32 Kevin Anderson. Del Potro had found his first Grand Slam semifinal since Wimbledon in 2013. He had played "my best match of the tournament," he said to ESPN on the court afterward.

He had done this one round after he came from the crypt, mulling retirement with labored breathing during a second set in the fourth round against Dominic Thiem, before winning unforeseeably, 1-6, 2-6, 6-1, 7-6 (7-1), 6-4, spurred by an untamed Grandstand crowd. "The other day I felt so bad, so bad," he said after 1 a.m. Thursday. Somehow, two nights after narrow escape and minutes after playing the king of the game who sought a third 2017 Grand Slam title, del Potro found himself saying, "I cannot believe to play another semifinal after all my injuries, after all my surgeries."