Madisons call the shots as US women sparkle

Tennis Australian Open: Keys stuns Kvitova; Serena motors on

Top seed Serena Williams and her older sister Venus led a foursome of American women into the Australian Open fourth round on Saturday, while men's top seed Novak Djokovic survived a nervous start to overcome a feisty Fernando Verdasco.

It is the first time four women from the traditional tennis powerhouse, which has relied on the Williams sisters for much of their Grand Slam success in the past decade, have made the last 16 at a major since Roland Garros in 2013.

The sisters were joined in the last 16 by the two Madisons -- Brengle and Keys -- who will play each other -- with the 19-year-old Keys upsetting twice Wimbledon champion Petra Kvitova 6-4, 7-5 in the last match of the day.

Twice champion Victoria Azarenka also advanced after a 6-4, 6-4 victory over 25th seed Barbora Zahlavova Strycova and will now meet last year's beaten finallist Dominika Cibulkova.

Djokovic was forced into a first set tie-break by former top-10 player Verdasco, while fifth seed Kei Nishikori also dropped the first set tie-break before he beat Steve Johnson.

Johnson and 19th-seed John Isner, who was beaten by Luxembourg's Gilles Muller, were the last American men in the singles competition, though North America will be represented in the fourth round by Canada's Milos Raonic.

Djokovic's match, which was temporarily halted before the third set as Verdasco took a timeout, did have another distraction with a marriage proposal in the stands that the world number one applauded when the woman accepted.

“I'm sure he was very happy when she said yes,” a smiling Djokovic said. “It's nice to see this moment.”

Men's champion Stanislas Wawrinka, pleased to be out of the glare of many people, also continued his quiet progression with a clinical victory over tricky left-hander Jarkko Nieminen.

While Azarenka continues to lurk as a danger to anyone in the top half of the draw, an ominous portent developed over the rest of the women's field with the Williams' sisters success.

The last time the siblings reached the last 16 at Melbourne Park, Serena went on to win her fifth Australian Open title.

The world number one beat Ukraine's Elina Svitolina 4-6, 6-2, 6-0, while 18th seed Venus also needed a set to get going before she beat Italy's Camila Giorgi 4-6, 7-6(3), 6-1 to make her first grand slam fourth round since Wimbledon in 2011.

The 34-year old will now meet women's sixth seed Agnieszka Radwanska who also continued her largely untroubled progress with a 6-0, 7-5 win over another American Varvara Lepchenko, while Serena will play the enigmatic Garbine Muguruza.

Bhupathi out

Veteran Mahesh Bhupathi went out of the mixed doubles competition following a first-round loss, even as India’s junior tennis players began their campaign on a positive note.

Bhupathi and his Australian partner Jarmila Gajdosova frittered away early advantage to lose 6-4, 6-7 (7), (8-10) to Chinese Taipei’s Hao-Ching Chan and Brit Jamie Murray.

In the junior competition, Pranjala Yadlapalli defeated South African Katie Poluta 6-4, 6-3 to enter the girls’ singles competition while Ojasvinee Singh lost 6-0, 4-6, 1-6 to American Olivia Hauger.

Among the boys, Sumit Nagal defeated American Michael Mmoh 6-2, 4-6, 6-4.