MELBOURNE: A tenacious Justine Henin returned to big-time tennis with a bang by downing fifth seed Elena Dementieva at the Australian Open, while Rafael Nadal kept his title defence on track.

Playing only her second tournament since making a comeback from an 18-month retirement, the seven-time Grand Slam champion showed she still has what it takes in a 7-5, 7-6 (8/6) epic that lasted almost three hours. The Belgian the Australian Open in 2004 and made this year’s tournament as a wildcard.

She next plays 27th seed Alisa Kleybanova with a potential quarter-final looming against fellow Belgian Kim Clijsters, who was given a thorough examination by Thai Tamarine Tanasugarn. Clijsters, also on the comeback trail after a break to start a family, triumphed 6-3, 6-3, but it was harder than the score suggested for the 15th seed. Her serve was broken in each set before she dug deep to win.

Spanish second seed Nadal was in rip-roaring form as he smashed hapless Slovak Lukas Lacko 6-2, 6-2, 6-2 to stay on track for a potential last eight meeting with Andy Murray. The Scotsman also looked ominous form with a flawless 6-1, 6-4, 6-3 mauling of Frenchman Marc Gicquel.

Fourth seed Juan Martin del Potro of Argentina was given a huge scare by American James Blake. The US Open champion battled for over four hours before winning a titanic five-setter to reach the third round 6-4, 6-7 (3/7), 5-7, 6-3, 10-8. Other top names also showing their credentials included Dinara Safina, Andy Roddick and Svetlana Kuznetsova.

Safina, the second seed who was beaten in the final last year by Serena Williams, posted a 6-3, 6-4 win over the Czech Republic’s Barbora Zahlavova Strycova but struggled.

She made nine more unforced errors (40 to 31) than her 57th-ranked opponent and had problems with her serve, facing multiple break points each time.

Unlike the high-profile Clijsters and Henin, Russian third seed Kuznetsova is flying under the radar and looked impressive in her 6-2, 6-2 defeat of countrywoman Anastasia Pavlyuchenkova.

The French Open champion said she had prepared well in the off-season and was ready to make an impact. Danish fourth seed Caroline Wozniacki downed Canada’s Aleksandra Wozniak 6-4, 6-2 while Belarussian seventh seed Victoria Azarenka blasted her way past France’s Stephanie Cohen-Aloro 6-2, 6-0.

In the men’s draw, Roddick ranted at the umpire after completing a straight sets win over Brazilian Thomaz Bellucci. The American seventh seed had just served out a 6-3, 6-4, 6-4 victory when he continued to argue over a Hawk Eye video review decision which narrowly went against him on the first of his two match points. He later apologised.