SYDNEY — World No. 4 Agnieszka Radwanska said it was “too hot to play tennis” and China's Li Na said it was like a sauna as the Sydney International was hit by a searing heatwave Tuesday. Poland's Radwanska, who reached last year's Wimbledon final, battled fearsome temperatures topping 40 degrees Celsius at the Olympic Park complex to brush past Japanese veteran Kimiko Date-Krumm 6-4, 6-3. While Radwanska reached the last eight, the major talking point was not the standard of play but the blistering heat ahead of next week's first Grand Slam event of the year at the Australian Open in Melbourne. “I think this is too hot to play tennis,” said Radwanska. “Even for players, for ball kids, for the people sitting out there, I think it's just too hot. “I think I would prefer to go on court at 11:00 p.m. and play a match.” All the day's scheduled matches were completed despite the searing heat. Li Na, who beat Japanese qualifier Ayumi Morita 6-1, 6-0, said she was reaching for the ice towels at each changeover. “I was feeling like playing in a sauna. At the first changeover I didn't use an ice towel. I was feeling the heat was coming and I was like, ‘What's going on'?” Li said. Two-time Grand Slam champion Svetlana Kuznetsova, who had to qualify here, beat former No. 1 Caroline Wozniacki 7-6 (4), 1-6, 6-2 while American qualifier Madison Keys defeated Zheng Jie of China 6-0, 6-4. In other matches, second-seeded Angelique Kerber and No. 3 Sara Errani of Italy also advanced to the quarterfinals. Kerber beat Galina Voskoboeva of Kazakhstan 6-2, 7-5 and Errani defeated Russian Maria Kirilenko 6-1, 6-1. In first-round men's play, sixth-seeded Radek Stepanek of Czech Republic defeated Guillermo Garcia-Lopez of Spain 6-2, 6-3 and Spain's Feliciano Lopez beat seventh-seeded Jeremy Chardy of France 6-7 (2), 7-5, 6-3. Jarkko Nieminen of Finland defeated qualifier Bjorn Phau of Germany 6-0, 6-1 and Australian wild-card entry John Millman beat Spain's Tommy Robredo 6-3, 6-4. Fabio Fognini of Italy beat Grigor Dimitrov of Bulgaria, who lost to Andy Murray in last week's Brisbane International final, 6-3, 6-1. Aussie qualifier upsets Melzer Australian qualifier Greg Jones produced the largest upset at the Heineken Open Tuesday, ousting sixth-seeded Jurgen Melzer of Austria 7-6 (7), 6-2 in the first round for his first ATP victory. Another qualifier to win was Igor Sijsling, who beat Robin Haase 3-6 6-3 7-5 in an all-Dutch match. In other first-round matches action, Lukas Lacko of Slovakia beat Paolo Lorenzi of Italy, 6-3, 6-3, and Santiago Giraldo of Colombia swept past Go Soeda of Japan 6-1 6-0. Gael Monfils rallied past Benjamin Becker of Germany 6-7 (2), 6-3, 6-4. Yen-hsun Lu of Taiwan beat Benoit Paire 6-3, 2-6, 6-2 with the Frenchman appearing to struggle with a hamstring injury. Cirstea eliminated American qualifier Lauren Davis beat second-seeded Sorana Cirstea of Romania 6-1, 6-3 in a rain-interrupted, second-round match Tuesday at the Hobart International. No. 3 Klara Zakopalova of the Czech advanced with a 6-4, 6-3 first-round win over Timea Babos of Hungary. Elena Vesnina of Russia beat fourth-seeded Yaroslava Shvedova of Kazakhstan 4-6, 6-2, 6-1 in a second-round match. Eighth-seeded Sloane Stephens of the United States, who lost to Serena Williams in the quarterfinals of the Brisbane International, advanced to the last eight with a 6-4, 6-0 win over Simona Halep of Romania. Ninth-seeded Mona Barthel of Germany also advanced to the quarterfinals, defeating Chanelle Scheepers of South Africa 7-6 (3), 7-5. — Agencies