NEW YORK -- The forehand from Catherine "CiCi" Bellis was so heavy it knocked the racket right out of the hands of Mexico's Renata Zarazua.
The shot actually crossed the net and Bellis, seeing Zarazua without a racket, sent the ball back to her. With no other option, Zarazua hit the ball with her right hand -- and both girls laughed.
It's good to be CiCi Bellis these days. The week after becoming the youngest player to win a match here at the US Open since Anna Kournikova in 1996, the 15-year-old Californian finds herself the No. 1 seed of the girls' junior tournament.
She played on the Grandstand -- a rarity for a junior match -- and defeated Zarazua 6-1, 6-3 in 65 minutes. Next up: Natalia Vikhlyantseva of Russia, who defeated Sandra Samir of Egypt 6-4, 6-3.
How has her life changed in a week?
Bellis' Twitter following has grown from 300 to better than 8,000. Instagram followers are up to nearly 4,000 from 1,200.
"That's way more pressure than playing," said Bellis, who's also trying to produce quality in her off-court social media moments.
There's a youth movement also underway in the women's main draw. Among the final 12, there were no fewer than three players aged 21 or younger. Belinda Bencic, 17, is the youngest quarterfinalist here since the daughter of her mentor, Melanie Molitor, did it in 1997. That would be Martina Hingis, who won the title that year at the age of 16.
This turn of events prompted our Baseline Buzz crew, ESPN.com tennis editor Matt Wilansky and senior writer Greg Garber, to hit a few verbal volleys on the subject.
Greg Garber: I really enjoyed the postmatch interview with Bellis. She's "amazed" by what's happened. Kim Clijsters, her idol, called her before her second match and asked her if she knew who she was. When she was asked if she liked being the No. 1 seed, I liked her answer: "I love being the No. 1 seed. I like being the target, the one everybody wants to beat. I don't feel any pressure. I feel more confident." That's the right attitude.
Matt Wilansky: It's amazing how far this kid has come. Bellis started this fortnight ranked 1,208th in the world and suddenly she is stealing back-page real estate from Roger Federer and Serena Williams. Someone lost in the teen swing this year, though, has been Bencic. Sunday night, she became the first player born after the construction of Arthur Ashe Stadium to win in this massive amphitheater. Her ascent is every bit as impressive as Bellis'; a year ago, Bencic came into the Open ranked 331st. Now here she is playing in her first-ever major quarterfinal.
Greg Garber: Bencic said she was nervous at the beginning of her match with Jelena Jankovic, but she looked calm and collected when she won each of the three set points on the No. 9 seed's racket. Bencic, after beating Jankovic -- in straight sets: "I think she had all the pressure because she needed to win. I could just enjoy." Bencic, ranked No. 58 among WTA players, has now defeated top-10 players in her past two matches, Jankovic and Angelique Kerber.
Matt Wilansky: Sunday night, Hingis garnered just about as much air time as Bencic. The parallels between the two are pretty striking. Bencic, the youngest quarterfinalist at any Slam since Nicole Vaidisova at the 2006 French Open, is competing in an era of older, stronger women. Who better than Hingis to teach her protégé how to compete in world of big-babe tennis? She did have 28 combined wins over the Williams sisters and Lindsay Davenport after all.
Greg Garber: And how about Aleksandra Krunic, the 21-year-old from Serbia? All she did was score her first top-30 victory over Madison Keys in the second round, then follow it up with a stunning defeat of No. 4-ranked Petra Kvitova, the Wimbledon champion, in the third before falling to Victoria Azarenka in a tight three-setter. All of this unexpected success has caused some housing turmoil. First, Krunic had to leave the apartment she rented in Queens last week because she didn't envision being here for the second week. She was forced to move from her midtown hotel Saturday and find another hotel room. She made $187,000 and a win would have given her $370,000 -- enough to by her own house in Queens.
Matt Wilansky: But barely enough to buy a 2014 US Open pullover. And we wondered how the USTA was going to fund its roof. Cha-ching! Krunic is a tremendous story, though. She came into this event as the lowest-ranked player in the draw. She stands just over 5-foot-6 but has the court coverage of someone much taller as we saw Monday night. No doubt folks here will remember Krunic's fighting spirit -- just as they will 20-year-old Dominic Thiem, one of your favorites, Mr. Garber. We saw him play Ernests Gulbis a few days ago, and the precocious Austrian came all the way back from a two-set deficit to win. I know I'm not the only one who thinks this kid has a bright future.
Greg Garber: The kid turns 21 in two days, so he can celebrate his arrival in the fourth round with a beer at one of the ubiquitous Irish bars in Manhattan. He was terrific against Gulbis, the No. 11 seed, and then Sunday night he pounded No. 19 Feliciano Lopez -- in straight sets. I'm trying to decide which is more impressive, a 17-year-old in the women's quarters or a 20-year-old in the fourth round of the men's draw. Thiem is the only unseeded player among the last 16. How about that?
Matt Wilansky: A good question, but I can tell you this. Both are more impressive than 20-year-old Eugenie Bouchard's performance Monday. She lost rather routinely to Ekaterina Makarova, meaning that for the first time since 1977, we will have eight different women's finalists in the four Grand Slams. And how's this little nugget for you: This is only the second time in the 46 years of the Open era that only one top-eight seed survived to play in the quarterfinals of any Slam. The other? The 2009 US Open. Youth movement? Parity? Call it what you want. The only thing I know for sure is that Serena Williams, the only top-10 ranked woman left in this year's draw, is doing a few cartwheels right about now.
Greg Garber: Oh, yes. She was genuinely excited to get to her first major quarterfinal of the year. Serena said actually "Yeah!" in her postmatch interview. The way she's playing -- she's dropped only 15 games in four matches -- I'd be shocked if she doesn't win this thing. That would give her 18 major titles (tying her with first-name legends Martina and Chrissie) and setting her up as the favorite for next year's Slams. Hard to believe she turns 33 at the end of the month.
Matt Wilansky: And it's hard to believe she faced any turmoil at all this year by the way she's played. Youth movement? It's here, but I'm not sure it's ready for championship trophies -- just yet.