More: Cincinnati Open 2024 results, schedule, live updates

Andreeva takes over Center Court in Cincinnati debut

World No. 13 Emma Navarro had all the momentum heading into Mason. Last week in Toronto, she moved to her career-best ranking after a semifinal run.

The 23-year-old American had won 15 matches against top 50 opponents this season but fell on Center Court to end Wednesday’s day session to No. 24 Mirra Andreeva in straight sets (6-2, 6-2) in a match that lasted just over an hour.

Making her Cincinnati Open debut, Andreeva picked up her 10th victory against a top 20 opponent by dominating on the first serve (82% win rate), capturing 4-of-8 break points and taking advantage of five Navarro double faults.

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World No. 1s take care of business

Center Court fans got to see both World No. 1s in action Wednesday.

Beginning with ATP No. 1 Jannik Sinner, who took over the top spot on the leaderboard in June. Sinner had struggled with hip injuries and bowed out in the quarterfinals in Montreal on Saturday. Sinner was pushed by 19-year-old American Alex Michelsen, but a strong serve (nine aces) helped the Italian advance in straight sets, 6-4, 7-5.

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WTA No. 1 Iga Swiatek opened the night session on Center Court with a 22-minute first set, breaking France’s Varvara Gracheva three times for a 6-0 victory. Thanks to seven service aces, she opened up a 5-2 lead in the second set and looked to close the match out in under an hour. But Gracheva fought back, breaking serve twice to force a 6-6 tie before winning a 10-8 tiebreak.

With the third set tied at two games apiece, Swiatek regrouped to break Gracheva’s serve twice, before holding her own serve for a 6-2 set win.

Swiatek’s downfall in the second set was her failure to put away break points. Gracheva saved five of the six break points she faced while serving. It’s something she must improve on before she faces Ukraine’s Marta Kostyuk in Friday’s Round of 16.

She said after the match that she felt tense during the second set and her style of play changed. One factor that may have contributed to that is she is playing on hard courts for the first time since competing in Biel, Switzerland in April.

“It’s going to be a little tougher now to feel the game, but that’s normal. We always need a couple of matches to get used to the surface. Here, for sure, the transition is probably the hardest from the slowest surface to the fastest surface,” Swiatek said.

Wozniacki triumphant in return to Cincinnati, WTA top 100

Facing off for the third time this year, Caroline Wozniacki finally got the better of Ukraine’s Anhelina Kalinina, winning 6-2, 6-4. It is her first win in Cincinnati since 2017; she had lost her opening match in 2023, 2019 and 2018.

Playing in the final match of the day on the Grandstand, Wozniacki used three break points to close out the first set, then relied on her serve in the second set. She served up all six of her aces in the second, double faulting just once.

The opening round win is another step in the right direction for Wozniacki. This time last year, she was ranked 632nd in the world and ended 2023 ranked 236th. In her match against Kalinina, she displayed more of the defensive style of tennis she has come to be known for.

Wozniacki will face Anastasia Pavlyuchenkova in the Round of 32.

WATCH: A look at the fan upgrades at the 2024 Cincinnati Open

Take a look at the new renovations in Mason for this year’s Cincinnati Open at the Lindner Family Tennis Center.