By Shrivathsa Sridhar MELBOURNE (Reuters) -Zheng Qinwen was the first big name to exit the women's draw at the Australian Open on Wednesday after the Olympic champion was stunned by Laura Siegemund while top seed Aryna Sabalenka made heavy weather of her second-round match before going through.

Last year's beaten finalist Zheng Qinwen blamed the lack of a warm-up event and a serve clock violation for her shock Australian Open exit in straight sets to German veteran Laura Siegemund on Wednesday.

Last year's runner-up Zheng Qinwen was knocked out of the Australian Open on Wednesday in the biggest shock so far but defending champion Aryna Sabalenka and two-time winner Naomi Osaka