MELBOURNE,  (Reuters) – Justine Henin passed the first  serious test in her comeback to the Australian Open when she  defeated Russia’s Elena Dementieva 7-5 7-6 yesterday in a  high quality match of unrelenting tension.

The Belgian, a wildcard entry as she does not even have a  ranking yet, dispelled any doubts about whether she can mix it  with the best after coming out of retirement with a performance  reminiscent of when she was world number one.

Fourth seed Juan Martin del Potro also provided a reminder  of the fighting qualities that enabled the towering Argentine to  topple Roger Federer in last year’s U.S. Open final when he beat  American James Blake 6-4 6-7 5-7 6-3 10-8.

Rafa Nadal erased any lingering concerns about his fitness  with an effortless 6-2 6-2 6-2 win over Slovakia’s Lukas Lacko  that brought a rare smile to the face of the number two seed  after a year plagued by injuries and self doubt.

“I think I did well, no?,” the Spaniard told reporters. “I  think I played the right way. A very good match, yeah.”

Kim Clijsters, Svetlana Kuznetsova and Dinara Safina had no  problems booking spots in the third round of the women’s draw  while Andy Roddick and Andy Murray did likewise in the men’s.

Henin was inspired by compatriot Clijsters’s fairytale win  at last year’s U.S. Open to make a comeback and said yesterday’s  victory over the world number five vindicated her decision.

“I wouldn’t believe I would live these kind of emotions  again,” she said in a courtside interview. “But the tournament  is not over for me yet.”

Clijsters, who took a two-year break before returning to the  sport last August, was given an easier workout by Thailand’s  Tamarine Tanasugarn and was able to raise her game when  necessary in a 6-3 6-3 victory while Kuznetsova beat fellow  Russian Anastasia Pavlyuchenkova 6-2 6-2.

MINOR STUMBLE

They are scheduled to meet in the fourth-round with the  winner to play Henin should the trio all keep winning in one of  the most open grand slam events in decades.

“This is for real,” third seed and French Open champion  Kuznetsova said. “This is for what you play for.”

Safina, last year’s runner-up, overcame a minor stumble when  serving for the match in her 6-3 6-4 victory over Barbora  Zahlavova Strycova.

The world number two is in the bottom quarter, safely away  from the Belgians, Russians and Williams sisters.

Danish fourth seed Caroline Wozniacki made a belated start  to her campaign at Melbourne Park, defeating Canada’s Aleksandra  Wozniak in a first-round match that was shuffled back because of  rain on the opening day.

Roddick eased to a 6-3 6-4 6-4 win over Brazil’s Thomaz  Bellucci but the match ended on a sour note when the American  argued with the chair umpire over a line call in the final game,  risking the possibility of a fine for foul language.

“I don’t do it for entertainment. I do it because I strongly  believe what I feel,” Roddick later explained. “I think if I  believe in something strongly enough, I’m pretty outspoken about  it.”

Murray was better behaved but unhappy with himself after  struggling with his serve in the windy conditions on Margaret  Court Arena during his 6-1 6-4 6-3 victory over France’s Marc  Gicquel.

“This is the highest level of the sport. That’s going to  happen,” he said.

Britain’s top female Elena Baltacha also made it through to  the third round by beating Ukraine’s 30th seed Kateryna  Bondarenko 6-2 7-5 but there was no more luck for Ireland’s new  sporting hero Louk Sorenson. He went down to American John Isner  6-3 7-6 7-5.