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.

She was forced to pull out of the Auckland Classic final on Sunday due to an abdominal injury. Read more at straitstimes.com.

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.