Tennis: Michael Venus through to quarter-finals at the Australian Open

Michael Venus and Raven Klaasen have progressed into the quarter-finals of the Australian Open. Photo / Getty Images.

New Zealand's top ranked doubles player Michael Venus and his South African playing partner Raven Klaasen have stormed into the quarter-finals at the Australian Open.

The sixth seeds thumped the duo of Marcelo Demoliner and Frederik Nielsen 6-3 6-1 in just over an hour.

Venus and Klaasen got off to the perfect start with a break in the opening game and served strongly throughout. They broke serve again in the ninth game to close out the set in 37 minutes, converting two of their three break points.

Last year's Wimbledon finalists got on with the job in the second set with two early breaks to race out to a 4-0 lead, before taking the set 6-1.

Venus and Klaasen did not face a break point against their serve in the entire match.

They will now face the unseeded combination of Leonardo Mayer and Joao Sousa for a place in the semifinals. Venus and Klaasen beat the South American pair in five sets en route to the Wimbledon final last year.

Meanwhile young Kiwi qualifier Valentina Ivanov has bowed out in the first round of the singles at the Junior Australian Open in Melbourne.

The 17-year-old winner of the New Zealand Championships title has lost 6-4 6-4 to Thailand's Mananchaya Sawangkaew.

Ivanov fought back from 4-2 down to level at 4-4 in the first set before her Sawangkaew broke serve and then closed out the set. The Kiwi had her chances in the second and served for a 4-1 lead. Instead, she was broken and it was 3-2. Ivanov was then broken again at 4-4 and Sawangkaew pushed on to close out the straight sets win.