WATCH: Serena explains shock loss to teenager Jan. 23, 2013, 6:31 p.m. Your browser does not support iFramesSerena Williams smashes her racquet. Pictures: AFPSloane Stephens has ousted tournament favourite Serena Williams.Serena Williams describes how ankle and back injuries contributed to her shock loss to US teenager Sloane Stephens at the Australian Open.In the biggest tournament upset so far, American 19-year-old Stephens beat the third seed 3-6 7-5 6-4.smh.com.au