Japan's Naomi Osaka withdrew from the semifinals of the Gippsland Trophy in Melbourne on Saturday as a precaution with an unspecified injury ahead of the Australian Open next week.

"Sorry to Tennis Australia and the fans to have to withdraw today. I have a niggling injury and in light of the AO on the horizon, I need to be cautious," Osaka said on the WTA Twitter account. "I look forward to competing next week."

Naomi Osaka on Feb. 5, 2021. (Kyodo)

Osaka, seeded second, had not looked to have sustained any injuries in her three matches at the warm-up tournament. Her semifinal opponent and seventh seed Elise Mertens of Belgium advanced to the final following her withdrawal.

The second-round win over Alize Cornet of France on Tuesday was Osaka's opening WTA match of 2021 and first since winning the U.S. Open in September. Osaka also beat Britain's Katie Boulter and Irina-Camelia Begu of Romania to reach the last four.

Osaka, 23, will be looking to claim her second Australian Open title when the tournament begins next Monday, following her win two years ago.

Australian Open organizers have delayed the start of the Grand Slam tournament by three weeks because of safety concerns amid the coronavirus pandemic.