Nadal makes strong start in Australia

(CNN) -- Rafael Nadal is on track to win his fourth successive grand slam after Marcos Daniel was forced to retire during their first-round match at the Australian Open on Tuesday.

World number one Nadal had already opened up a 6-0 5-0 lead before the Brazilian suffered a knee injury after 47 minutes of the match.

Nadal, a nine-time major winner, is hoping to become the first player since Rod Laver in 1969 to win four consecutive grand slams.

"I think I played right," the 24-year-old told the ATP Tour's website ahead of his next match against American debutant Ryan Sweeting, who is ranked 116th.

"I played some good shots, some long shots. The serve can be a little bit better. That's the only point that I think I can improve."

The Australian Open should be in February!

British fifth seed Andy Murray progressed to round two after his opponent also became injured.

Murray, who was a beaten finalist in Melbourne last year, led Slovakia's Karol Beck 6-3 6-1 4-2 when the world number 101 succumbed to a shoulder problem.

The match lasted for one hour and 42 minutes before Beck withdrew, meaning the 23-year-old Murray will now face Illya Marchenko of the Ukraine who beat Spain's Ruben Ramirez Hidalgo.

"I thought it was a pretty good match," said Murray.

"Obviously you'd rather finish the match off without your opponent being hurt, but it does happen quite a lot. So you just have to move on and get yourself ready for the next round."

Juan Martin del Potro scored a victory on his return to grand-slam action as he defeated Israel's Dudi Sela 7-6 6-4 6-4.

Argentina's Del Potro, the 2009 U.S. Open champion, has not played in one of the four majors since last year's Melbourne Park tournament after struggling with a wrist injury.

"Today I played good tennis again," the former world number four said.

"But I'm really enjoying this week. I met with all the players, especially the top-10 players. They supported me when I was very bad. So now I am face to face with them I can say thank you."

Del Potro will now play the 2006 Australian Open champion Marcos Baghdatis, who beat Slovenia's Grega Zemlja 3-6 7-5 6-1 4-6 6-2.

Australia's Lleyton Hewitt and David Nalbandian of Argentina played out a five-set clash which lasted four hours and 48 minutes at the Rod Laver Arena in a rematch of the 2002 Wimbledon final.

Nalbandian eventually sealed a 3-6 6-4 3-6 7-6 9-7 victory, with the final set lasting 93 minutes, as he avenged that defeat and also his reverse to hewitt in the 2005 Austalian Open quarterfinals.

Lithuania's Ricardas Berankis will be Nalbandian's second-round opponent after he beat another Australian Marinko Matosevic 6-4 6-2 7-5.

France's Jo-Wilfried Tsonga came from two sets down to claim a 4-6 2-6 6-2 6-3 6-4 triumph over Philipp Petzschner of Germany.

Tsonga, seeded 13th, eventually won the match after 194 minutes to set up a tie against Andreas Seppi after the Italian defeated Arnaud Clement.

America's John Isner hit 26 aces on his way to a 6-3 7-6 6-3 win over Florent Serra of France.

Isner is set to face Radek Stepanek of the Czech Republic in the second round, who advanced at the expense of Deni Gremelmayr.