Watch: Sofia Kenin's bizarre mental lapse in Charleston, stops play to call challenge

Sofia Kenin had a bizarre Charleston Open moment on Thursday as the American tennis star appeared to forget that the electronic line calling system was in place and wanted to use a challenge. Serving for the match at 5-4 in the second set and with the game being tied to 15/15, the 2020 Australian Open champion thought that Daria Kasatkina's ball was wide and she stopped play and circled the place where she thought the ball landed. If this happened several years earlier when line umpires wer