- Third seed Roger Federer shrugs off criticism and injury worries to win opening match
- Swiss star cruises to 7-5 6-2 6-2 victory over Russia's Alexander Kudryavtsev
- Second seed Rafael Nadal also through in straight sets after beating qualifier Alex Kuznetsov
- World No. 1 Novak Djokovic begins his Australian Open title defense on Tuesday
Having been criticized by his great rival Rafael Nadal for not taking a stand over players' rights, Roger Federer began his bid for a fifth Australian Open title with a comfortable straight-sets victory on Monday.
The 16-time grand slam champion joined Nadal in round two, matching the Spaniard's smooth progress in Melbourne with a 7-5 6-2 6-2 win over Russia's Alexander Kudryavtsev.
World No. 172 Kudryavtsev, making his tournament debut, matched the Swiss third seed early on as he battled to 5-5 in the first set. But Federer shrugged off pre-tournament back concerns as he conceded only four more games to beat a player who won just three ATP Tour matches last year.
The 30-year-old, whose last major title came in Melbourne in 2010, will next play Germany's 93rd-ranked Andreas Beck.
"I really tried to put in an effort to every point, play as hard as I could, first to see how the back felt, try to get into it, hopefully win, and then see how I feel tomorrow," Federer said, before insisting his relationship with Nadal had not been affected.
"Things are fine between us, you know. I have no hard feelings towards him. It's been a difficult last few months in terms of politics within the ATP, I guess, trying to find a new CEO and chairman. That can get frustrating sometimes. But for me, obviously nothing changes in terms of our relationship."
His fellow former world No. 1 Nadal came into the tournament having announced to international reporters that he would no longer be making statements about grievances over scheduling and pay.
He then told Spanish media on Sunday that he thought ATP player council president Federer should take more of a public role over issues such as where the Davis Cup fits into the busy calendar.
"His (position) is easy: do not say anything, all positive, I am a 'gentleman,' others get burned. We each have our opinion and maybe he likes the circuit. Me too, I like it, and I think it's better than most sports. That does not mean you cannot be better and that you should change things that are bad," the 25-year-old said ahead of Monday's 6-4 6-1 6-1 win over Ukraine-born American qualifier Alex Kuznetsov.
"I say a lot of good things about tennis, because thanks to this sport I have had experiences in my life I could never have dreamed of, but to finish your career with pain in all areas of your body is not positive.
"He finishes his career as fresh as a daisy because he is physically privileged, but neither Murray nor Djokovic and I are fresh as a daisy."
Nadal, the 2009 champion, had hoped he was over his injury problems going into the two-week event, but revealed after his opening win that he needed an MRI scan after hurting his right knee yet again in practice.
"I was much more scared about the first match than the rest, because today now I have 48 hours to the next match," said Nadal, who retired hurt against Andy Murray in 2010 and suffered a hamstring injury in last year's quarterfinal defeat by David Ferrer.
"So I am really confident that having had the worst feeling that I ever had in my knee yesterday and today was able to play -- I have fantastic hope that's going to happen the same for after tomorrow."
He also admitted some remorse over his previous day's attack on Federer.
"Probably I am wrong telling that to you, especially because these things can stay, must stay in the locker room," Nadal said. "I always had a fantastic relationship with Roger. I still have a fantastic relationship with Roger."
Nadal, who could meet Federer in the semifinals, will next play Germany's former world No. 2 Tommy Haas.
The 33-year-old Haas, now ranked 190th after years of injury problems, beat Ukraine-born U.S. resident Denis Kudla in four sets.
Argentine 11th seed Juan Martin del Potro, the last man outside of defending champion Djokovic, Nadal and Federer to win a singles grand slam, progressed with a 2-6 6-1 7-5 6-4 win over France's 91st-ranked Adrian Mannarino.
The 2009 U.S. Open champion will next play Slovenia's world No. 103 Blav Kavcic.
Czech seventh seed Tomas Berdych also went through to round two along with American No. 8 Mardy Fish and No. 16 John Isner, Spanish No. 10 Nicolas Almagro and No. 18 Feliciano Lopez, Ukraine's No. 13 Alexandr Dolgopolov and Swiss No. 21 Stanislas Wawrinka.
Isner will next play 2006 semifinalist David Nalbandian, whose Finnish opponent Jarkko Nieminen retired with a stomach muscle injury at 6-4 4-2 down the day after winning the rain-delayed Sydney Invitational title.
Wawrinka will play Marcos Baghdatis, the 2006 runner-up from Cyprus who lost in the Sydney semis on Friday.
Fish faces Colombia's 71st-ranked Alejandro Falla while Berdych plays Belgium's Olivier Rochus.
Australian teenager Bernard Tomic eliminated Spanish 22nd seed Fernando Verdasco -- a semifinalist in 2009 -- and the 19-year-old will next play American Sam Querrey.
Djokovic begins the defense of his title against Italy's Paolo Lorenzi on Tuesday, while last year's runner-up Andy Murray faces American teenager Ryan Harrison.