Melbourne, Jan 20 (DPA) Defending champion Rafael Nadal eased to a straight set victory Wednesday into the third round of the Australian Open while fourth seed Juan Del Potro, in a contrasting win, was stretched to five sets.
Nadal, the second seed, was untroubled by Slovak outsider Lukas Lacko 6-2, 6-2, 6-2, winning in less than two hours to improve his career record at Melbourne Park to 23-4.

“I played more relaxed, the second round always is easier to play,” said Nadal. “You are more adapted to the conditions.”

Del Potro battled before finally getting past American James Blake 6-4, 6-7 (3), 5-7, 6-3, 10-8, with the Argentine US Open champion taking treatment on his elbow and Blake getting help with a shoulder.

The winner fired 69 winners and broke seven times in the marathon.

Four other seeds turned in straight-set wins, following the no-stress example set by Nadal.

British fifth seed Andy Murray overcame Frenchman Marc Gicquel 6-1, 6-4, 6-3 and will next face another Gallic opponent in the third round after Florent Serra defeated Finn Jarkko Nieminen 3-6, 6-4, 5-7, 7-6(4), 7-5.

Seventh seed Andy Roddick, appearing fully recovered from a knee injury which ended his 2009 season early, hammered Brazilian Thomaz Bellucci 6-3, 6-4, 6-4.

Chile’s number 11 seed Fernando Gonzalez beat Turkish lucky loser Marsel Ilhan 6-3, 6-4, 7-5. The 12th seed, Gael Monfils of France, beat Croatian Antonio Veic 6-4, 6-4, 6-4.

On the women’s side, Russians Dinara Safina and Svetlana Kuznetsova both advanced into the third round.

Former number one Safina beat Barbora Zahlavova Strycova 6-3, 6-4 while third seed Kuznetsova overcame compatriot Anastasia Pavlyuchenkova 6-2, 6-2.

“It’s good that I won the match, but still there is so much room to improve,” said Safina. “Deep inside, you know you have so much more to bring out.”

The comeback dream continued for seven-time Grand Slam winner Justine Henin. The Belgian, who came out of retirement this month, battled to defeat Russian fifth seed Elena Dementieva 7-5, 7-6 (8-6) in a struggle of well over two hours.

Another one-time top-ranked player, Serbian eighth seed Jelena Jankovic, advanced over Brit Katie O’Brien 6-2, 6-2.

Belgian’s power pair from the US Open - semi-finalist Yanina Wickmayer and champion Kim Clijsters - also won.

Wickmayer put out Italian 12th seed Flavia Pennetta 7-6(2), 6-1 and Clijsters, seeded 15th, came back from 0-3 in the second set to top Thai Tamarine Tanasugarn 6-3, 6-3.

“I feel like I’m good enough on the day to beat my opponents,” said the double Grand Slam winner Clijsters. “It’s not with my best tennis yet, but hopefully I can save that when it’s really necessary.

“Today Tammy was very tricky. I was actually surprised to see she was still playing. But it’s very hard to read her game.”

Britain’s 83rd-ranked Elena Baltacha’s win over Kateryna Bondarenko of Ukraine 6-2, 7-5 duplicated her career-best showing at the majors.