By Nick Mulvenney
Dec 29 (Reuters) - Roger Federer and Serena Williams had contrasting 2013 seasons but both kick off their new campaigns at the Brisbane International this week showing no signs just yet of calling time on their illustrious careers.
Born just a month apart and each with 17 grand slam singles titles to their name, Federer and Williams could justifiably claim to be the best tennis players of their generation, if not of all time.
This year, though, it was American Williams who led the way with 11 titles, including the coveted trophies at the French and U.S. Opens, and winning 78 of 82 matches to regain the number one ranking.
Federer slumped to sixth in the world after winning just the one title at Halle and failing to get to a grand slam final for the first time since 2002.
While admitting the season had been difficult at times, Federer said on his arrival in Brisbane that he was feeling fitter than he had for more than 18 months and was not about to be pushed into retirement.
"People are always going to jump in and say 'this is it', and that's what happened this year," the 32-year-old told a news conference.
"Critics are a part of the game. But they are the last guys to push me out of this game.
"Deep down I am doing it because I love the game. And now I don't want to waste any more opportunities."
Federer, top seed in the absence of double defending champion Andy Murray, will not be joined by the newest member of his coaching team, Stefan Edberg, until he reaches Melbourne.
The Brisbane field should not test the Swiss too greatly, though, with big-serving South African Kevin Anderson the only top 20 player in his half of the draw. Japan's Kei Nishikori is seeded second.
Williams had no sooner capped her stellar 2013 season by winning the WTA Championships than started plotting what she views as a long overdue sixth triumph at Melbourne Park.
Williams pulled out of the Brisbane tournament in 2012 after turning on her left ankle in her second round tie before exiting the Australian Open in a fourth round upset at the hands of Ekaterina Makarova.
Last year, she won the Brisbane title without losing a set but, hampered by another ankle twist in her first round match, was knocked out in the Australian Open quarter-finals by compatriot Sloane Stephens.
Having missed the 2011 Australian Open after cutting her foot by stepping on some glass in a restaurant, Williams is keen to return to winning ways at a tournament she won five times in eight years from 2003.
"I hope to be the one standing up in the end, and it's for sure my next goal," Williams said after her tour championships triumph in Istanbul.
"Seeing that I didn't do as well as I want to there, actually the past few years, so my goal is just to go a year in Australia without twisting an ankle. That's what I'm going to start with."
The American top seed faces a much tougher draw than Federer, who also has a first round bye, with, if the seedings hold up, Maria Sharapova and Australian Open champion Victoria Azarenka standing in the way of her title defence.
World number 10 Caroline Wozniacki was removed from that path, however, when she withdrew from the tournament on Sunday as a precautionary measure after hurting her right shoulder.
"I wanted to start off the year well," Wozniacki told reporters. "That's why I made the decision to withdraw from here, just because I didn't feel like there was a need to make it worse before going into the Open as well."
Williams will start her campaign in the second round against German Andrea Petkovic, who beat American Bethanie Mattek-Sands 6-4 7-5 in the opening day's action on Pat Rafter arena on Sunday. (Editing by Amlan Chakraborty)