Former world number one Martina Hingis [Images] breezed into the fourth round of the Australian Open when she crushed Czech Iveta Benesova 6-4, 6-1 on Saturday.

Third seed Amelie Mauresmo of France [Images] reached the fourth round when her opponent Michaella Krajicek retired from their match suffering from heat stress.

The Frenchwoman, who has indicated that Hingis' comments ahead of their 1999 final, where the Swiss called her 'half a man' still rankles, has a chance to stop the Hingis bandwagon in the quarterfinal.

Hingis needed only 66 minutes to dismiss her unseeded opponent on a scorching hot Rod Laver Arena at Melbourne Park to take another significant step in her comeback after injury forced her into an early retirement four years ago.

Benesova, 22, took an early 3-1 lead after breaking Hingis's serve in the fourth game but the Swiss broke back immediately and then stamped her authority on the match in a clinical display.

Hingis, a beaten finalist on her last Melbourne appearance in 2002, will play either Australian Samantha Stosur or Austrian Sybille Bammer for the chance to reach the quarter-finals.

Mauresmo had raced through the first set of their third-round match on Rod Laver Arena 6-2 when Krajicek called for assistance as temperatures exceeded 35 Celsius (95 Fahrenheit).

Tournament trainers checked Dutchwoman Krajicek's temperature and pulse as the 17-year-old sat courtside before Krajicek decided not to continue.

Her withdrawal came only minutes after officials invoked the tournament's extreme heat policy.

Mauresmo, runner-up in the 1999 Australian Open, will play 16th seeded Czech Nicole Vaidisova in the fourth round.

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