Naomi Osaka's Australian Open campaign has taken on an element of doubt after the four-time Grand Slam champion and former No. 1 suffered an apparent injury Sunday while playing the final of a WTA tournament in Auckland.

Former world No. 1 Naomi Osaka retired from the ASB Classic final in Auckland on Sunday due to an abdominal injury after winning the first set against Clara Tauson.

The former world No. 1 and four-time Grand Slam champion retired from the final of the WTA Auckland Open, the last tune-up before the Australian Open, with an apparent medical issue on Sunday. She had been leading Denmark's Clara Tauson 6-4 before her exit left Tauson as the tournament's champion.

Osaka had won the first set of the final 6-4 against Denmark's Clara Tauson when she spoke to her coach Patrick Mouratoglou, the chair umpire, and a tour trainer before deciding to withdraw.

Naomi Osaka has had one of her best weeks during her comeback but just like the last good week on the tour, it has been blighted by a sudden injury which in this case saw her lose the final of the ASB Classic in Auckland to Clara Tauson.

Clara Tauson will meet Naomi Osaka in the ASB Classic final on Saturday, January 4.In Tauson’s last action, she was defeated by Jasmine Paolini 6-1, 5-7, 4-6 in the Round of 64 at the China

Naomi Osaka's quest for a first title in four years ended in heartbreak as the former world number one retired with an injury after winning the opening set of the Auckland Classic final against Denmark's Clara Tauson on Sunday.

Naomi Osaka will be competing in the final of the ASB Classic in New Zealand on Sunday, where she will face Denmark’s Clara Tauson for the first time. The tennis player won 6-4 6-2 in the semi-final against Alycia Parks.