Poland's Agnieszka Radwanska stretched her winning streak to six matches with a straight sets victory over Japanese veteran Kimiko Date-Krumm in brutal heat at the Sydney International on Tuesday.
As temperatures soared above 41 degrees Celsius (106 Fahrenheit), the tournament top seed overcame an early break before wearing down 42-year-old Date-Krumm, winning 6-4, 6-3 in 70 minutes. (Also read: Players sweat it out in Sydney 'sauna')
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.
"So far I feel fine. I don't have any problems and it's (the) beginning of the year," said Radwanska, who next plays Italian Roberta Vinci.
"It's not like in the end of the year that we play so many tournaments, so many matches and we can think sometimes it's too much and it's better not to play everything before the Grand Slam.
"But so far I'm feeling good. I think it's still good preparation for Australian Open."
Radwanska played in her first Grand Slam final last year at Wimbledon where she lost to Serena Williams in three sets. At one stage last year she reached world number two before slipping to her current four.
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 number one Caroline Wozniacki went down in a titanic duel with former French and US Open champion Svetlana Kuznetsova 7-6 (7/4), 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 number one Jelena Jankovic went out to Vinci in three sets.
In the men's event Spaniard Feliciano Lopez recovered from losing the opening set tiebreaker to knock out French seventh seed Jeremy Chardy, 6-7 (2/7), 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.
Italy's Fabio Fognini eliminated Grigor Dimitrov in straight sets, with the Bulgarian coming off losing to Andy Murray in last weekend's Brisbane International final.