Roger Federer says he feels a return to top form could be months away but he is in good shape for a tilt at next week's Australian Open in Melbourne.
For the first time in 11 years the 17-time Grand Slam title winner failed to reach the final of any of the four majors in 2013.
His streak of reaching at least the quarter-finals of 36 consecutive Grand Slam events also ended last year and he fell out of the top five in the world rankings for the first time in more than a decade.
But rather than contemplate retirement, the Swiss 32-year-old's response has been to train harder in the off-season, hire Stefan Edberg as his new coach and experiment with a new larger racquet.
Federer said he was confident he could revive his career, even if it does not happen immediately.
"I trained probably harder than all the guys ranked ahead of me in the off-season, because they went off to play exhibitions, like I did last year," Federer told reporters late Wednesday after a charity event at Melbourne Park with Rod Laver.
"So that goes with me. I did full-on months, which I haven't done in a long time and my body held up for that.
"Then I played singles and doubles in Brisbane (last week) ... I really feel I'm on my way back.
"Who knows? Maybe I'm playing my very best in March or April is my feeling.
"But I still feel there's a lot possible right now."
During Wednesday's charity event, Federer traded shots with 75-year-old Australian legend Laver, something he said as a tennis historian was an "absolute dream come true".
He then won a three-setter against French world number 10 Jo-Wilfried Tsonga, on a night that raised more than Aus$1 million ($890,000) for his foundation, which supports education for underprivileged children in southern Africa.
Federer said promoting such causes was part of his motivation for continuing to play, as was simple enjoyment of the game.
But it was the lure of winning more tournaments he said he feels most strongly.
"The thrill of holding up a trophy and the thrill of being before match point is an amazing one," Federer said.
"That's probably deep down why I'm playing. But of course there's so many other things I can do at the same time."