Ostapenko won Saturday's exhibitoon in a deciding match tiebreak, 6-2, 3-6, 10-5. Serena Williams out

ABU DHABI, UAE 
Less than four months after becoming a mother, defending Australian Open champion Serena Williams kicked off her 2018 against the highest caliber of opposition on Saturday: a fellow Grand Slam winner.

While not an officially sanctioned WTA match, two of last season's major champions squared off on the final day of the 10th annual Mubadala World Tennis Championships, traditionally an exhbition event for male players in Abu Dhabi.