Caroline Wozniacki of Denmark hits a return against Marketa Vondrousova of the Czech Republic on Day 3 during the National Bank Open at Stade IGA on August 9, 2023 in Montreal, Canada. Photo: AFP
Wozniacki had returned with a bang from a more than three-year layoff on Tuesday, winning 6-2, 6-2 against 115th ranked Kimberly Birrell.
But the 33-year-old Danish star found Vondrousova a tougher proposition, with the ninth seed claiming a 6-2, 7-5 victory to set up a last 16 clash with Coco Gauff.
Vondrousova looked to be motoring towards a brisk victory after taking a 6-2, 3-0 lead over Wozniacki.
Vondrousova then had a point for a 4-0 lead but doubled faulted twice to let Wozniacki off the hook.
The veteran then rallied brilliantly to take a 4-3 lead and had a break point in the eighth game for a 5-3 lead.
Vondrousova however held for 4-4 and then earned a break for a 6-5 lead before serving to love to seal victory.
Elsewhere on Wednesday, world number one Iga Swiatek entered the competition with an opening 7-6 (8/6), 6-2 win over Karolina Pliskova.
The victory left reigning US Open champion Swiatek needing victory over Karolina Muchova on Thursday to ensure she will hold on to the number one ranking for a 72nd week.
Her clash with the Czech Republic's Muchova on Thursday is a rematch of the duo's three-set battle in the French Open final earlier this year, won by Swiatek.
"It's nice to have some challenges and overcome them," Swiatek after Wednesday's win. "It wasn't an easy first round, but I'm happy that I stayed solid, and I could close it in the first set."
Swiatek, who entered the tournament fresh from a victory in Warsaw last month, is now relishing another duel with Muchova.
"We have to be ready for the next match and kind of expect that anything can happen because tennis can be pretty unpredictable," Swiatek said.
"You know, one player can have a bad day. At the same time the other one can play the best tennis of their life."
In other games on Wednesday, 2022 Wimbledon champion Elena Rybakina finally closed out victory over Jennifer Brady in a match that had started on Tuesday before being halted.
Rybakina, seeded three, edged past the returning Brady 6-7(3/7), 7-6(7/5), 6-3 and will now face unseeded Sloane Stephens of the United States in the last 16.
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