The fourth seed needed over two and a half hours of grueling play to fend off Czech Karolina Muchova 6-7(5) 6-4 6-2. In a first meeting between both ladies, they exchanged early breaks in the first set before a tiebreak eventually ensued. Osaka was unable to contain her errors, gifting Muchova the tiebreak after sending a forehand long on set point.

The World No.10 seemed more comfortable in the second set, as she raced to a 2-0 lead. The crucial break proved sufficient, as Osaka held serve to win the set and level the match at one set apiece.

It was Muchova who was unable to prevent the errors from flying off her racket in the final set, as Osaka grabbed an early break. The fourth seed grabbed a second break to hold a commanding 4-0 lead, and closed out the match with the 12th ace of the day. She next faces 16th-seeded Ukrainian Dayana Yastremska, who defeated American Bernarda Pera 7-6(5) 4-6 6-3 in her second round match.

Fifth seed Aryna Sabalenka also faced a stern challenge in her second round match, as she battled American qualifier Cici Bellis. The Belarusian lost the opening set in a one-sided tiebreak, but overpowered her opponent to advance 6-7(1) 6-4 7-5 in two hours and 20 minutes. Although Bellis was able to match her opponent in the first set, Sabalenka's experience and power were too much for the youngster. Sabalenka next faces American Jessica Pegula, who defeated compatriot Amanda Anisimova 7-5 6-2 in the second round.

In perhaps one of the biggest upsets of the day, defending champion Madison Keys was eliminated by Tunisian Ons Jabeur in straight sets. The seventh seeded American was never able to find her rhythm, and had no answer for Jabeur's trickery and shot-placement. Jabeur prevailed 6-4 6-1 to advance to the third round, where she faces American Christina Mchale.

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