Poland’s Agnieszka Radwanska stretched her winning streak to six matches with a straight-set victory over Japanese veteran Kimiko Date-Krumm in brutal heat at the ATP/WTA Sydney International on Tuesday.

As temperatures soared above 41 degrees Celsius, the tournament top seed overcame an early break before wearing down 42-year-old Date-Krumm, winning 6-4, 6-3 in 70 minutes.

Radwanska, 23, went into the Sydney event immediately off the back of a win in Auckland without dropping a set, and is in great form heading into next week’s Australian Open in Melbourne.

German second seed Angelique Kerber overcame Kazakh qualifier Galina Voskoboeva 6-2, 7-5 and said playing in the heat was going to help her in Melbourne next week.

“I think it's a good preparation for Melbourne. Melbourne’s weather can be the same,” Kerber said. “So to have matches in this heat and also to just prepare before Melbourne.”

Former World No. 1 Caroline Wozniacki went down in a titanic duel with former French and U.S. Open champion Svetlana Kuznetsova 7-6(4), 1-6, 6-2.

China’s fourth seed Li Na, who won in Sydney two years ago, breezed past Japanese qualifier Ayumi Morita, 6-1, 6-0, while Italian third seed Sara Errani downed Russian Maria Kirilenko, 6-1, 6-1. Chinese Zheng Jie bowed out to American qualifier Madison Keys 6-0, 6-4, while Serbia's former World No. 1 Jelena Jankovic went out to Vinci in three sets.

Tomic posts win

In the men’s event, Bernard Tomic won the all-Australian night match with the country’s No. 1-ranked player Marinko Matosevic 6-3, 6-4.

Tomic continued his impressive unbeaten start to the southern summer season, including the prized scalp of World No. 1 Novak Djokovic at last week’s Hopman Cup mixed teams event in Perth.

Spaniard Feliciano Lopez recovered from losing the opening set tiebreaker to knock out French seventh seed Jeremy Chardy, 6-7(2), 7-5, 6-3, while Australian wild card John Millman surprised Spaniard Tommy Robredo 6-3, 6-4.

Czech sixth seed Radek Stepanek accounted for Spanish qualifier Guillermo Garcia-Lopez in straight sets and Finland’s defending champion Jarkko Nieminen eased past German qualifier Bjorn Phau for the loss of one game.

Monfils scrapes through

Mercurial Frenchman Gael Monfils battled into the second round of the Heineken Open in Auckland on Tuesday, displaying flashes of brilliance as he came from behind to keep his injury comeback on track.

The former World No. 7 beat German Benjamin Becker 6-7(2), 6-3, 6-4 in the New Zealand tournament, a warm-up for this month’s Australian Open Grand Slam later this month.

The results:

At Sydney: ATP/WTA International: Men: First round: Radek Stepanek bt Guillermo Garcia-Lopez 6-2, 6-3; Feliciano Lopez bt Jeremy Chardy 6-7(2), 7-5, 6-3; Jarkko Nieminen bt Bjorn Phau 6-0, 6-1; John Millman bt Tommy Robredo 6-3, 6-4; Fabio Fognini bt Grigor Dimitrov 6-3, 6-1; Kevin Anderson bt Aljaz Bedene 6-3, 3-6, 6-3; Bernard Tomic bt Marinko Matosevic 6-3, 6-4; Ryan Harrison bt Roberto Bautista Agut 2-1 (retd.).

Women: Second round: Agnieszka Radwanska bt Kimiko Date-Krumm 6-4, 6-3; Sara Errani bt Maria Kirilenko 6-1, 6-1; Li Na bt Ayumi Morita 6-1, 6-0; Angelique Kerber bt Galina Voskoboeva 6-2, 7-5; Dominika Cibulkova bt Ekaterina Makarova 7-6(3), 1-6, 7-6(1); Roberta Vinci bt Jelena Jankovic 3-6, 6-4, 7-6(4); Madison Keys bt Zheng Jie 6-0, 6-4.

At Auckland: ATP Heineken Open: First round: Greg Jones bt Jurgen Melzer 7-6(7), 6-2; Igor Sijsling bt Robin Haase 3-6, 6-3, 7-5; Jesse Levine bt Daniel King-Turner 6-2, 6-2; Gael Monfils bt Benjamin Becker 6-7(2), 6-3, 6-4; Lukas Lacko bt Paolo Lorenzi 6-3, 6-3; Santiago Giraldo bt Go Soeda 6-1, 6-0; Alejandro Falla bt Grega Zemlja 6-4, 3-1 (retd.); Yen-Hsun Lu bt Benoit Paire 6-3, 2-6, 6-2.

At Hobart: WTA International: Second round: Lauren Davis bt Sorana Cirstea 6-1, 6-3; Elena Vesnina bt Yaroslava Shvedova 4-6, 6-2, 6-1; Mona Barthel bt Chanelle Scheepers 7-6(3), 7-5; Sloane Stephens bt Simona Halep 6-4, 6-0.

First round: Mona Barthel bt Ashleigh Barty 2-6, 6-0, 6-1; Bojana Jovanovski bt Maria-Teresa Torro-Flor 6-0, 7-6(7); Klara Zakopalova bt Timea Babos 6-4, 6-3.

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