The Western & Southern Open women’s draw was blown wide open after top seeds Karolina Pliskova and Sofia Kenin were beaten in straight sets on Sunday in New York.
Top seed Pliskova fell 7-5 6-4 to Veronika Kudermetova, her 11 aces offset by nine double faults and the fact she offered Kudermetova 13 break point opportunities – of which the Russian converted three.
Kenin, the reigning Australian Open champion and second seed, fell to Alize Cornet 6-1 7-6(7) after trailing 6-1 5-2.
In the men’s event, six of the eight seeds in action won their matches on Sunday, with No.4 seed Stefanos Tsitsipas cruising to a 6-1 6-3 win over Kevin Anderson to reach the third round.
Also advancing to the last 16 was seventh seed David Goffin, a 7-6(6) 6-4 winner over Borna Coric.
Fellow seeds Diego Schwartzman, Karen Khachanov, Grigor Dimitrov and John Isner all won their first-round matches in straight sets.
It tournament marks the first ATP event in five-and-a-half months due to the sport's coronavirus-related suspension. Novak Djokovic, the top seed, was forced to pull out of the doubles event with a neck injury but remains in the singles draw, where he opens against Ricardas Berankis in the second round.
MEN'S DRAW: Western & Southern Open
Kenin committed a whopping 53 unforced errors in the one-hour, 43-minute loss to Cornet.
“Preparation-wise, I was playing well. I had a great practice four or five days, and then today just it completely fell apart,” lamented Kenin, who was unable to convert two set points in the tiebreak.
Pliskova said she found it tough to transition to New York’s quick hard courts.
"I don't know what's the reason to make it this fast, but, yeah, there is plenty of time to get used to it, but apparently one week was not enough for me,” said the world No.3, who lead Kudermetova 4-1 in the first set.
Kudermetova next plays either No.14 seed Elise Mertens – a 6-0 6-2 winner over Rebecca Peterson on Sunday – or Kristina Mladenovic for a place in the quarterfinals.
Cornet, meanwhile, will face the winner of the second-round meeting between Victoria Azarenka and Caroline Garcia.
Garcia, a former world No.4 who has since slipped to 49th, beat Sloane Stephens 6-3 7-6(4) on Sunday. Stephens, a US Open champion in 2017, has now lost seven of her eight singles matches in 2020.
WOMEN'S DRAW: Western & Southern Open
In all, eight qualifiers advanced to the second round of the women’s draw on Sunday; among them was Jessica Pegula, who beat in-form Lexington champion Jennifer Brady in straight sets.