Tennis fans are disappointed as one of its most dominant stars was forced to make a sudden and painful exit from the first Grand Slam of the year. Naomi Osaka, a two-time champion at Melbourne Park, officially withdrew from the Australian Open on Saturday just hours before she was set to take the court for her third-round match. The 28-year-old former world No. 1 revealed that an abdominal injury sustained during her previous match has left her unable to compete.