MELBOURNE, Australia – Rafael Nadal sat in his hotel room in “unbelievable pain,” his right knee cracking and his leg cramping. He wondered if he’d be able to play his first-round match at the Australian Open.

He already had plenty on his mind going into the year’s first Grand Slam tournament. There was his ailing shoulder and his spat with Roger Federer over player conditions on the tour, a rare clash between these respectful rivals that since has been smoothed over.

After hours of medical tests and treatment, Nadal decided to play but was “scared” when he took the court against American qualifier Alex Kuznetsov. Judging by the scoreline, the outcome looked very matter of fact: Nadal won 6-4, 6-1, 6-1, but it was anything but that for the 2009 Australian Open champion.

On the tournament’s tumultuous eve Sunday, Nadal used a Spanish language news conference to criticize Federer for holding back while letting others “burn themselves” in the push for changes on the tour.

Nadal and Federer are in the same half of the draw at a major for the first time since 2005 after Novak Djokovic surpassed them both in 2011 by winning three of the four Grand Slam titles and taking the No. 1 ranking.

Third-seeded Federer started his bid for a 17th major title with a 7-5, 6-2, 6-2 win over Alexander Kudryavtsev of Russia. He then just as quickly batted away any notion of a simmering feud with Nadal. Ever the statesman, Federer conceded that players differed on ways of resolving certain issues and “things are fine between us.”

“We can’t always agree on everything,” he said in a diplomatic tone suggesting that even if there is any tension it will remain a private matter. He also praised Nadal for maturing into a leader.

Nadal didn’t apologize for what he said about Federer but did say he was sorry for publicly airing locker-room divisions. He said he will not answer any questions for the rest of the tournament about player grievances regarding schedules or prize money.

“I always had fantastic relationship with Roger. I still have fantastic relationship with Roger,” he said. “Just I said we can have different views about how the tour needs to work. That’s all.”

Nadal has been dealing with a sore shoulder for months and has indicated he will take time off next month to let it heal. But he surprised everyone when he walked onto Hisense Arena with a heavily taped knee Monday.

After his opening victory, he disclosed – saying it was to avoid any mystery – that he’d felt a “crack” and later experienced “unbelievable pain.” He said he tried to stretch his leg but he had no movement in his knee.

Tests attributed the problem to a pinched tendon, and he said he should be fine for his next match after a day off.

Nadal was among a host of leading players with injuries coming into the tournament. Federer said he wasn’t bothered by the back problem that forced him to withdraw from a tournament in Doha this month.

Defending champion Kim Clijsters beat Portuguese qualifier Maria Joao Koehler 7-5, 6-1 and didn’t seem troubled by the hip spasms that caused her to retire during the Brisbane International semifinals. Li Na, who lost to Clijsters in last year’s Australian final but rebounded to win the French Open, defeated Ksenia Pervak of Kazakhstan 6-3, 6-1.

Top-ranked Caroline Wozniacki had to wait until the last match on Rod Laver Arena to get her tournament under way and test the left wrist she hurt in Sydney last week. She wasted little time dispatching Australia’s Anastasia Rodionova 6-2, 6-1.

“I got a bit nervous about my wrist, but I am happy I could play full out (Monday),” she said.

Temperatures rose to 93 degrees at Melbourne Park on Monday, and a strong wind unsettled some players who had spent previous days practicing in unseasonably cool conditions.

Australian teenager Bernard Tomic had plenty of support as he rallied for a 4-6, 6-7 (3), 6-4, 6-2, 7-5 victory over No. 22-seeded Fernando Verdasco of Spain. Tomic, a Wimbledon quarterfinalist last year, is the host nation’s best hope of ending a barren stretch for Australian men at the Open dating to 1976.

“(Monday) wasn’t fun, it was torture,” Tomic said. “I don’t know how I found the energy to lift, how I did it, but I thank the crowd.”

Eighth-seeded Mardy Fish, the highest-ranked U.S. man, defeated Gilles Muller had a 6-4, 6-4, 6-2 to progress along with 2009 U.S. Open champion Juan Martin del Potro, No. 7 Tomas Berdych, No. 10 Nicolas Almagro and No. 13 Alexandr Dolgopolov.

Verdasco, the 2009 semifinalist, was among the four seeded men ousted in the first round.

No. 19 Flavia Pennetta of Italy was the highest ranked of the three seeded women who lost Monday. Bethanie Mattek-Sands had her chances against No. 8 Agnieszka Radwanska but lost 6-7 (10), 6-4, 6-2.

Top men’s seed Novak Djokovic got his title defense off to a great start Tuesday, downing Italy’s Paolo Lorenzi 6-2, 6-0, 6-0.

After surrendering her opening service game with a double-fault, Wimbledon champion Petra Kvitova won 12 consecutive games in a 6-2, 6-0 win Tuesday over Russia’s Vera Dushevina to move into the second round of the Australian Open.

Wearing the purple color synonymous with Wimbledon, the No. 2-ranked Kvitova underlined her growing stature on the women’s tour by not giving Dushevina a second chance. The 21-year-old Czech broke her Russian rival’s serve three times in each set and finished off Tuesday’s opening match on Rod Laver Arena in an hour.

Kvitova reached the quarterfinals here last year at the start of a season in which she surged up the rankings. Last week, she missed a chance to overhaul Caroline Wozniacki’s No. 1 ranking when she lost in the Sydney International semifinals. She needed to win the Sydney tournament to take the top ranking.

But she gets another chance at Melbourne Park, where she’s one of six women who can finish No. 1.

“I have great memories of this court from last year, when I came out, everything came back in my head,” she said in a post-match TV interview. “It was nice.”

It gave her the confidence to win her first major later in the year.

The Wimbledon title “was a surprise for me,” she said. “Nobody expected it or knew I could be No. 2.”

Other women advancing included No. 27 Maria Kirilenko, who beat Australian hope Jarmila Gajdosova 6-4, 6-2, Canada’s Aleksandra Wozniak and Shahar Peer of Israel.

Men’s No. 5 seed David Ferrer advanced in straight sets, 6-1, 6-4, 6-2, over Rui Machado of Portugal. Germany’s Philipp Petzschner routed Czech Republic’s Lukas Rosol 6-0, 6-0, 6-2 to advance.