Rafael Nadal has a new injury scare, a tendon problem in his right knee that nearly forced him to forfeit a first-round match at the Australian Open that he managed to win easily.

Roger Federer, defending champion Kim Clijsters and top-seeded Caroline Wozniacki, also bothered by injuries coming into the tournament, all advanced to the second round in more routine fashion and appeared as if they were over their ailments.

That wasn't the case with Nadal. Bothered by a left shoulder injury late last year, Nadal had his right knee heavily taped during his 6-4, 6-1, 6-1 win over Alex Kuznetsov. The injury occurred in the most innocent of ways, sitting in a chair in his hotel room when he felt "a crack" in his knee followed by pain."

He had an MRI scan late on Sunday that showed no major damage to his knee, but before that, the incident left him thinking "I wasn't 100 percent sure I would have a chance to play."

Federer, who pulled out of a tournament in Doha two weeks ago with back soreness, began the quest for his 17th grand slam title, and first since the 2010 Australian Open, with a 7-5, 6-2, 6-2 win over qualifier Alexander Kudryavtsev.

Defending women's champion Clijsters opened with a 7-5, 6-1 win over Portuguese qualifier Maria Joao Koehler. Wozniacki easily beating Australia's Anastasia Rodionova 6-2, 6-1 in the last match of the evening on Rod Laver Arena. In the first featured match of the tournament, third-seeded Victoria Azarenka won 12 straight games to finish off Heather Watson 6-1, 6-0 in 67 minutes in the opening match on center court.

Eighth-ranked Agnieszka Radwanska fended off American Bethanie Mattek-Sands 6-7 (10), 6-4, 6-2. Other women advancing included No. 16-seeded Peng Shuai of China, No. 20 Daniela Hantuchova of Slovakia, No. 22 Julia Goerges, No. 26 Anabel Medina Garrigues of Spain and Eleni Daniilidou of Greece beat 41-year-old Kimiko Date-Krumm of Japan 6-3, 6-2.

Most of the local attention yesterday was on 19-year-old Bernard Tomic, who rallied from two sets down to beat No. 22-seeded Fernando Verdasco 4-6, 6-7 (3), 6-4, 6-2, 7-5.