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

Novak Djokovic and Carlos Alcaraz swept into the third round of the Australian Open in the wake of women's top seed Aryna Sabalenka on Wednesday as the rain returned and Olympic champion Zheng Qinwen bowed out.

Novak Djokovic made a slice of Grand Slam history on his way into the Australian Open third round on Wednesday but last year's women's finalist Zheng Qinwen was knocked out in the biggest shock so far.

Last year's runner-up Zheng Qinwen was knocked out of the Australian Open on Wednesday in the biggest shock so far while defending champion Aryna Sabalenka had to battle serve jitters to make the third round.