Serena Williams' ex-coach identifies why Zheng Qinwen looks 'cranky' at times

Rennae Stubbs doesn't want to label Zheng Qinwen "a bad loser" but believes that the 22-year-old doesn't deal with defeats particularly well and that's probably why she looks "cranky" at times. This year, the Chinese tennis star was one of the most successful players after winning the Paris Olympics and finishing as runner-up at the Australian Open and the WTA Finals. But while her game often gets praised, some fans have taken an exception with how the world No. 5 acts after matches - it di