US Open Day 10: Carlos Alcaraz wins a 5-hour all-timer against Jannik Sinner

The future of tennis arrived Wednesday evening in Flushing Meadows in the form of Carlos Alcaraz vs. Jannik Sinner. Even after five hours, it hadn't overstayed its welcome.

Alcaraz, the 19-year-old Spaniard tabbed by many as the young player most likely to take over the sport after the age of the Big 3, defeated Sinner 6-3, 6-7, 6-7, 7-5, 6-3 to advance to his first career Grand Slam semifinal.

Along the way, the two young power hitters — Sinner is 21 years old — exchanged winners and lengthy rallies well into the night. The tennis was impossibly high level, with 119 winners combined. The match eventually ended at 2:50 a.m. ET, the latest ending to a match in US Open history, and lasted five hours and 15 minutes, the second-longest match in tournament history.

As soon as Alcaraz hit his final ace to clinch the win, he collapsed to the court. It wasn't long before commentator Patrick McEnroe was interviewing him and calling the match one of the greatest in the history of the sport.

We cannot emphasize enough how ridiculous the shot-making got during this night.

The match was high-octane from the first game, beginning with a straightforward set win for Alcaraz before Sinner nailed things down. Two straight sets ended in tiebreak wins for the Italian, and he had Alcaraz on the ropes in the fourth, serving for match point twice.

Alcaraz staved off defeat to take the fourth set, but opened the fifth set sloppily enough for Sinner to go up a break. At that juncture, the phenom found a gear only accessible to 19-year-olds at 2 a.m. and won four straight games, breaking Sinner back and once again for good measure.

Even with Alcaraz at his highest level, Sinner still didn't go down quietly:

With most of the country asleep, Alcaraz took what should be his big step forward. Sinner did too, but sadly picked the most inconvenient possible time to do it. Now, Alcaraz will have roughly 36 hours to recover before he's set to face Francis Tiafoe in the semifinals.

Should he win, he will already be assured of the No. 1 ranking on the ATP Tour, but there would obviously be a much bigger prize still at stake.

Iga Swiatek ends Jessica Pegula's run with straight sets victory

An American woman won't be hoisting the trophy at Arthur Ashe Stadium on Sunday. Poland's Iga Swiatek managed to overcome a serious challenge from Jessica Pegula to earn a spot in the semifinals. In a gritty and competitive match that lasted nearly two hours, Swiatek bested Pegula 6-3, 7-6(4). This is Swiatek's first trip to the US Open semifinals, and her third trip to a Grand Slam semifinal.

The score doesn't come close to telling the story of this match. Both women played fiercely, constantly challenging each other to up their game and dealing with the peaks and valleys of their own play. Things looked a little dicey for Swiatek at the start. It took barely 15 minutes for her to go down a game and a break at 3-2. But Swiatek rallied, freezing Pegula at three games as she ripped off an impressive run of points to win the next three games. Pegula had been solid, but began to get frustrated as the unforced errors piled up.

The second set was a different story entirely. It looked like Swiatek was on her way to an easy two-set win when Pegula flipped the switch and took her game to a new level. Suddenly she was everywhere the ball was, hitting shots at wild angles and making Swiatek rush and run around the court. Up 5-4, Swiatek had a few opportunities to serve for the match, but continued to let Pegula bully her around the court until the score was tied 6-6.

There were a few moments when it seemed like Pegula was seeing through the matrix and had figured out how to defeat Swiatek. But a few stray errors ended Pegula's run at the US Open, just short of making her first career Grand Slam semi.

Frances Tiafoe onto semifinals after statement win over Andrey Rublev

For the first time in his career, 24-year-old Frances Tiafoe has made it to a Grand Slam semifinal. Playing at Arthur Ashe Stadium, he defeated Andrey Rublev in a stunning and entertaining three-set match, winning 7-6(4), 7-6(0), 6-4. He's the first Black American man to make the US Open semifinals since Arthur Ashe himself in 1972.

There was a startling lack of breaks in this match, just one over three whole sets and two tiebreaks. Tiafoe and Rublev traded games throughout the entire match, but Tiafoe was the first to really take control. In the first-set tiebreak, he practically cruised to the required seven point victory. The second set was just as tight as the first, and it ended the same way: Tiafoe bashed his way to an easy tiebreak win.

There was hardly any sign of the over-emotional Tiafoe we've seen for a few years. Working with a new coach, he's discovered how to overcome that and regroup after bad shots or games. You could see it in his game, especially compared to Rublev. Tiafoe played loose and free, confident and comfortable from any point on the course. Rublev was wound tighter than a drum, and was obviously more comfortable playing from the baseline than coming closer to the net.

The third set is when Tiafoe began to struggle very tiny bit. He had some missed shots, and wasn't entirely prepared for Rublev to start returning better. But as he had in the previous two sets, he found a way to overcome. He stayed calm and focused while Rublev yelled and stewed, and managed to close out the match without a third-set tiebreak. And that single break of serve in the entire match? It belonged to none other than Tiafoe.

Before Tiafoe, Andy Roddick and John Isner were the last American men to make the quarterfinals at the US Open, way back in 2011. And there hasn't been an American man in the US Open semifinals since Roddick in 2006. Tiafoe ended that drought on Wednesday, and he's poised to do even more. Until Wednesday, Roddick was the last American man to make a Grand Slam semifinal, which happened in 2009. In that same year, he was also the last American man to make a Grand Slam final. That long drought could end on Friday when Tiafoe plays the winner of the match between Jannik Sinner and Carlos Alcaraz.

It's been nearly 20 years since an American man has won a Grand Slam title. The last to do it was Roddick at the 2003 US Open, which took place less than a year before Roger Federer would start his period of dominance and usher in the era of the Big Three. If Tiafoe keeps playing like he did on Wednesday, he could be the man to end that drought.

Aryna Sabalenka comes out swinging, defeats Karolina Pliskova

Aryna Sabalenka wasn't messing around when she walked onto the court at Arthur Ashe Stadium. She overpowered former US Open champ Karolina Pliskova 6-1, 7-6(4) to advance to her second consecutive US Open semifinal.

Sabalenka came out swinging, both figuratively and literally. At six feet tall, she's a powerful player, and she positively overwhelmed Pliskova in the first set. Pliskova looked shellshocked, and managed to win just one game in the first set to avoid being totally blanked.

It took just 28 minutes for Sabalenka to crush Pliksova in the first set, but Pliskova raised her game in the second set, putting Sabalenka off balance. Sabalenka started hitting the ball into the net quite a bit and wasn't as dominant as she was when the match began. She started returning with too much power, sending the ball way past the baseline and once into the stands. But Sabalenka found ways around that. She didn't just use power against Pliskova, she also had a soft touch.

Pliskova and Sabalenka battled in the second set, eventually knotting the score at 4-4. Pliskova did manage to stave off elimination several times, matching Sabalenka at 5-5, and refusing to give in when she was just two points away from a Sabalenka win. She forced a tiebreak to keep her semifinal hopes alive, but Sabalenka overpowered her, just as she'd been doing all match.