Teenager Agnieszka Radwanska caused the biggest shock so far at this year's US Open by beating defending champion Maria Sharapova in the third round.
Radwanska is ranked 32 in the world
Sharapova was 2-0 in the third set, but Radwanska, 18, won the last six games for a famous 6-4 1-6 6-2 win.
Three other teenagers made the last 16 on a day of surprises in New York.
Victoria Azarenka, 18, saw off Martina Hingis 3-6 6-1 6-0, Agnes Szavay, also 18, upset Nadia Petrova 6-4 6-4 while Tamira Paszek, 16, beat Patty Schnyder.
Hingis, celebrating the 10th anniversary of her victory at the US Open, lost her way dramatically after winning the first set against the Belarussian.
"You can see the new generation coming up," she said. "They're very dangerous. I knew it's not going to be easy."
WOMEN'S DRAW: BOTTOM HALF
Szavay v Vakulenko
Azarenka v Kuznetsova
Chakvetadze v Paszek
Peer v Radwanska
Eighth seed Schnyder led by a set and 4-1 before losing 4-6 6-4 7-6 (7-1) to Austrian Paszek, who also reached the fourth round at Wimbledon this year.
And a day of upsets was completed in the evening sessions when Israel's Shahar Peer came through a titanic tussle with Nicole Vaidisova 6-4 3-6 7-6.
The departures of Sharapova, Hingis, Schnyder, Petrova and Vaidisova decimated the bottom half of the draw.
Fourth seed Svetlana Kuznetsova is the highest-ranked player remaining.
She beat Spain's Anabel Medina Garrigues 6-3 6-1 and will now be a strong favourite to reach the final in New York.
She made so many errors on her second serve
Justine Henin, Venus and Serena Williams, Jelena Jankovic and Ana Ivanovic are all in the opposite half of the draw.
Sharapova's double-fault count reached 12 as she lost her way against former junior world number one Radwanska.
It was Sharapova's earliest Grand Slam exit since she lost in the third round at Flushing Meadows in 2004.
"I could sit here and blame the wind and blame my opponent. But there are no excuses," Sharapova said.
"I'm not going to throw myself a pity party here."
The Russian said she had not been put off by Radwanska moving about when receiving serve, adding: "I don't worry about what my opponent is doing."
But Radwanska believes her tactics paid off.
The 18-year-old stood well inside the baseline to receive serve, often standing on the service line before retreating at the last moment.
"I knew that she hates it if somebody moves when she is serving," she said.
"So I knew I had a chance if I did it and she made so many errors on her second serve."
Radwanska, seeded 30, will play either Peer for a place in the quarter-finals.
Szavay, the 18-year-old Hungarian, is playing for the first time at Flushing Meadows this year, won 6-4 6-4 against Russian Petrova.
World number 31 Szavay will now play Ukrainian Julia Vakulenko, who beat Maria Kirilenko of Russia 6-2 6-4.
Petrova, who made 29 unforced errors and hit just 15 winners, was also beaten in the third round at last year's US Open.
Russian sixth seed Anna Chakvetadze made quick work of her third-round match, defeating India's 26th-seeded Sania Mirza 6-2 6-3 in 53 minutes.