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The grounds at the US Open were not busy on Saturday. It felt as if the air had been taken out of the site on the first day of the post-Serena Williams era.

There was a lot of excitement in the stands, in the lines at the food court, and in the traffic. The hottest tickets in town were her matches, as thousands of people gathered to catch a glimpse of her.

She lost and that was the end of her illustrious career. The match between Nadal and Gasquet on Saturday felt like a flop.

There was something happening on Sunday. Someone.

The crowd grew louder and louder as Coco Gauff faced a tough battle against Zhang Shuai in the second match of the day. "Let's go, Co-co" was chanted frequently by the chair umpire.

It doesn't feel right. Is it possible that the stadium chanted my name? Gauff spoke after the match. On the changeover, I tried not to smile. I was trying to be present.

Gauff made it to the French Open final.

While three matches stand in the way of her first Grand Slam title, it is obvious that she is one of the game's next big superstars.

She's not the only one who wants to reignite the crowd.

Frances Tiafoe celebrates after defeating No. 2-ranked Rafael Nadal on Monday. JUSTIN LANE/EPA-EFE/Shutterstock

One of the biggest upsets of the tournament took place on Monday afternoon, when the 22-time major champion, Nadal, was defeated by the 19-year-old American, who was making his Grand Slam debut.

The American has entertained crowds with his fearless play and powerful hitting. He was able to put it all together in the fourth round. Even though Nadal is one of the most popular players on the tour, the crowd was turned on their feet as the match progressed, and by the end, everyone was on their feet.

The two-time French Open champion advanced to the quarterfinals on Monday with a three-set comeback win. The 21-year-old won 12 of the last 16 games after falling in the first set.

In the evening, 21-year-old Jannik Sinner became the youngest person since 2008 to reach the quarterfinals at all four majors when he defeated Ivashka.

Carlos Alcaraz defeated Marin Cilic in the early hours of Tuesday morning to advance to the quarters at the US Open. He had a surprise run to the same round in 2021. A group of supporters stayed in the stands, chanting his name and waving Spanish flags, until the very end of his fourth-round match. There is an hour and a half later.

Nick Kyrgios is a 27 year old Australian with seemingly unlimited skill and showmanship. He reached his first major final at Wimbledon in July after years of not living up to the expectations.

He's into his first US Open quarters after a statement victory. He is the favorite to win the title. His personal life is not without controversy even though he seems to be on the court. The man was accused of domestic assault by his former partner and has a hearing in October.

Carlos Alcaraz made it to the quarterfinals at the US Open for the second year in a row. JUSTIN LANE/EPA-EFE/Shutterstock

Tennis appears to have reached a changing of the guard moment. It has been anticipated for a long time as the biggest names have gotten older.

In addition to Williams' retirement, Roger Federer has been out for over a year as he recovers from a right knee surgery, Novak Djokovic is playing a limited schedule due to his unvaccinated status, and Venus Williams is playing less than usual. While Nadal has won two major titles this year, he has dealt with a slew of injuries over the past 13 months and was handed his earliest Grand Slam exit since last year.

This is the first major since the start of the 2005 season to not have Nadal, Djokovic or Nadal in the quarters. Since 2003 there has been no "Big Three" or "Williams" in the US Open's quarterfinals. Swiatek is the only Grand Slam champion left, and he has never won the US Open.

"I think it's great for tennis that Nick is playing great tennis," said the man in a "GOAT" sweatshirt. He's packing stadiums when he's playing a game. Alcaraz is a good person. It was a bit of an odd thing. It's my thing. The people are behind me.

A new era is cool.

Several players have looked like they might break through in the past. Naomi Osaka seemed to be a sure thing with her four major titles, but she has struggled on and off the court over the past year. She lost in the first round.

He came well short of defending his title this week, despite taking over the top ranking earlier this year.

Almost all of the women who have won Grand Slam titles in the past several years have been unable to repeat their success after their breakthrough moment.

Winning isn't the only thing that makes someone a star. The younger players have the "it" factor of charisma and authenticity, and it's no surprise to see them fill stadiums and earn new fans with every victory.

Gauff's popularity is still growing. She spoke at a Black Lives Matter rally in 2020 and wrote "End gun violence" on the camera at the French Open after the school shooting in Texas.

Gauff had never won a match on the famous tennis court. She has played every game of the tournament in the past. She had her first three scheduled in front of Williams.

She appreciated the marquee placement.

Gauff said that he was surprised that he was placed on Ashe. It occurred again in the second round. When Serena was playing, I thought it would continue.

It's like a perfect lineup for viewers. I will be closing out with the GO AT. That is insane.