NEW YORK -- Frances Tiafoe's vision was blurry from the tears. He was thrilled -- overwhelmed, even -- when the last point was over and it hit him that, yes, he had ended Rafael Nadal's 22-match Grand Slam-winning streak on Monday and reached the US Open quarterfinals for the first time.

"I felt like the world stopped," Tiafoe said. "I couldn't hear anything for a minute."

Then Tiafoe found himself "losing it in the locker room" when he saw that NBA superstar LeBron James gave him a Twitter shoutout.

"Bro," Tiafoe said, "I was going crazy."

What meant the most to Tiafoe about his 6-4, 4-6, 6-4, 6-3 victory over No. 2 seed Nadal in the fourth round at Flushing Meadows, though, was looking up in his Arthur Ashe Stadium guest box and knowing his parents, Constant and Alphina, were there.

"To see them experience me beat Rafa Nadal -- they've seen me have big wins, but to beat those Mount Rushmore guys?" said Tiafoe, a 24-year-old American player seeded 22nd at the US Open. "For them, I can't imagine what was going through their heads. I mean, they're going to remember today for the rest of their lives."

His parents emigrated to the United States from Sierra Leone in West Africa amid its civil war in the 1990s. They ended up in Maryland, where Constant helped construct a tennis training center for juniors then became a maintenance man there. Alphina, Tiafoe said, was "a nurse, working two jobs, working overtime through the nights." Tiafoe and his twin brother, Franklin, were born in 1998, and soon would be spending hour upon hour where Dad's job was, rackets in hand.

Maybe one day, went the dream, a college scholarship would come of it.

"It wasn't anything supposed to be like this," Frances Tiafoe said Monday evening, hours after by far his biggest victory.

He is the youngest American man to get this far at the US Open since Andy Roddick in 2006, but this was not a case of a one-sided crowd backing one of its own. Nadal is about as popular as it gets in tennis, and he heard plenty of support as the volume raised after the retractable roof was shut in the fourth set.

Nadal was 31-2 in majors against Americans entering Monday's match and had won 27 straight since losing to James Blake in 2005.

"It's something to tell the kids, the grandkids: 'Yeah, I beat Rafa,'" Tiafoe said with a big smile.

He served better than Nadal. More surprisingly, he returned better too. And he kept his cool, remained in the moment and never let the stakes or the opponent get to him. Nadal, 36, from Spain, had won both of their previous matches -- and every set they played too.

"Well, the difference is easy: I played a bad match, and he played a good match," said Nadal, who has won a record 22 Grand Slam titles. "At the end, that's it."

This surprise came a day after Tiafoe followed along on TV as his pal Nick Kyrgios "put on a show" and eliminated No. 1 seed and defending champion Daniil Medvedev. That makes this the first US Open without either of the top two seeded men reaching the quarterfinals since 2000, when No. 1 Andre Agassi exited in the second round and No. 2 Gustavo Kuerten in the first.

That was before Nadal, Novak Djokovic (who has 21 Grand Slam titles) and Roger Federer (who has 20) began dominating men's tennis. Djokovic, 35, did not enter this US Open because is not vaccinated against COVID-19 and was not allowed to enter the United States; Federer, 41, has undergone a series of operations on his right knee and last played at Wimbledon in 2021.

This year's US Open is just the second major since the start of 2005 without any of Federer, Djokovic and Nadal in the quarterfinals. The other was the 2020 US Open, when Federer and Nadal didn't play and Djokovic was defaulted against Pablo Carreno Busta in the round of 16.

Now come the inevitable questions about whether their era of excellence is wrapping up.

"It signifies that the years go by," Nadal said. "It's the circle of life."

Tiafoe now will meet No. 9 Andrey Rublev, who beat No. 7 Cameron Norrie 6-4, 6-4, 6-4 earlier Monday.

No. 11 Jannik Sinner rallied from two games down in the fifth set to beat Ilya Ivashka 6-1, 5-7, 6-2, 4-6, 6-3 and clinch a spot in all four Grand Slam quarterfinals this year.

Sinner, who turned 21 in August, became the youngest player to reach the quarterfinals of all four Grand Slam events in a season since Djokovic was 20 in 2007.

Sinner was down 3-1 in the fifth set but rallied to win five straight games to close out the unseeded Ivashka. Sinner won 12 break points in the match and dug deep in the fifth, showcasing why the rising Italian is considered as a potential star. Sinner joins Matteo Berrettini as Italian men in the US Open quarterfinals.

Sinner will play the winner of Monday night's final match between 2014 US Open champion Marin Cilic and No. 3 Carlos Alcaraz.

Cilic is the last remaining major champion left in the men's draw. If he loses to the heavily favored Alcaraz, it will be only the third time in the Open era (since 1968) that a men's major tournament has a quarterfinal lineup without an ex-champion, according to ESPN Stats & Information research.

Nadal won the Australian Open in January and the French Open in June. Then he made it to the semifinals at Wimbledon in July before withdrawing from that tournament because of a torn abdominal muscle.

Nadal competed only once in the 1½ months between leaving the All England Club and arriving in New York, where he has won four trophies.

He tweaked his service motion, tossing the ball lower than he normally does so as not to put as much strain on his midsection. There were plenty of signs on Monday that his serve was not in tip-top shape: nine double-faults, a first-serve percentage hovering around 50%, five breaks by Tiafoe.

Earlier in the tournament, Nadal lost the first set of his first-round match. He did the same in the second round, when he also accidentally cut the bridge of his nose and made himself dizzy when the edge of his racket frame bounced off the court and caught him in the face.

Still, on Monday, Nadal appeared on the verge of turning things around when he broke early in the fourth set and went ahead 3-1.

Tiafoe told himself: "Stay in it. Stay with him."

That's tied to two key areas Tiafoe credits with helping make him a stronger player of late: an improved in-match mindset and a commitment to fitness.

"Rafa is there every point," Tiafoe said. "I've been known to have some dips in my game at times, where it's like you're watching [and thinking], 'What's that?!' That was my thing, match intensity."

No concern now; he grabbed the last five games. The next-to-last break came for a 4-3 edge in the fourth set, when Nadal put a backhand into the net, and Tiafoe skipped backward toward the sideline for the ensuing changeover, his fist raised.

Fifteen minutes later, Tiafoe broke again, and it was over. This represents the latest significant step forward for Tiafoe, whose only previous trip to a Grand Slam quarterfinal came at the 2019 Australian Open -- and ended with a loss to Nadal.

When one last backhand by Nadal found the net, Tiafoe chucked his racket and put his hands on his head. He looked toward his guest box in the stands -- Mom, Dad, brother, girlfriend, Washington Wizards All-Star Bradley Beal, others -- then sat in his sideline chair and buried his face in a towel.

"It was just wild," Tiafoe said. "My heart is going a thousand miles an hour. I was so excited. I was like: Let me sit down. Yeah, I've never felt something like that in my life, honestly."

The Associated Press contributed to this report.