Kuznetsova is the second big name to crash out in two days
Third seed Svetlana Kuznetsova followed world number one Ana Ivanovic out of the US Open after a 6-3 6-7 (1-7) 6-3 defeat by Katarina Srebotnik.
The 2004 champion, who was runner-up last year, slumped to a demoralising loss in two hours and 20 minutes.
"I didn't play badly," said Kuznetsova. "She just played her best game."
Second seed Jelena Jankovic battled for more than two hours before beating Zheng Jie 7-5 7-5 but Lindsay Davenport lost 6-1 7-6 to Marion Bartoli.
The 32-year-old American was overpowered by 12th seed Bartoli in the first set of what may have been her last Grand Slam match.
The former champion, with a partisan crowd willing her on, saved a match point at 5-3 in the second before forcing the tie-break.
It's tough to make any kind of decision in a rash moment
But her lack of match practice came back to haunt her as errors at crucial moments - particularly on serve - allowed Bartoli to edge it.
Davenport has made no playing plans beyond the US Open, but said she had not reached a decision on whether she will retire.
"It's tough to make any kind of decision in a rash moment," she said.
"There was no decision made before the tournament and I don't think it's time to make a certain statement now."
Bartoli goes on to face Austrian Sybille Bammer in the fourth round, while Jankovic will play rising star Caroline Wozniacki in the last 16 after the Dane beat Victoria Azarenka 6-4 6-4.
The Serb is now the only one of the top three seeds still in the tournament following the exits of Ivanovic and now Kuznetsova.
Russian Kuznetsova played a commanding tie-break to draw level at one set all against Srebotnik, more renowned for her doubles exploits.
But Srebotnik broke early in the decider and the Slovenian maintained control.
Serving for the match, she continued to play aggressively, sealing victory on her third match point when Kuznetsova went long with a return.
"I was fighting and I wanted so much to win that match. She served very well, she came to the net many times, she was more aggressive than I was," added Kuznetsova.
"For me it's a special tournament, I wanted to play very well here.
"She started coming in and I was not able to keep her back or come in myself."
Jankovic was pushed hard before getting the better of Wimbledon semi-finalist Zheng.
The Chinese number two saved four match points in a marathon 12th game of the second set, but after 11 deuces, Jankovic eventually came through.
After spending nearly three hours on court in her previous match, the 23-year-old insisted she would prefer to win in a more mundane manner.
"I wish I didn't have any drama in my matches, I wish I would win nice and in a simple way," she said.
"Just cruise through the match and that's it, but as long as you win, that's what matters."