Japan's Naomi Osaka bowed out of the WTA Finals on Friday with an injury, retiring after losing the first set to Dutchwoman Kiki Bertens.Osaka, ranked fourth in the world after winning her first two tour titles, including the U.S. Open, was playing in the tour finals for the first time, but failed to win a match.She began the match against Bertens with the top of her left thigh taped, and sought medical treatment during the first set, which she went on to lose 6-3."...Didn't want it to end like this but I'm really proud of how I did here," Osaka said in a post on her Twitter account.As rumo…READ FULL ARTICLE