Roger Federer revealed he had to conquer mental doubts before ending his season in style by winning the ATP World Tour Finals for a record sixth time.
The greatest player of all time failed to win a Grand Slam for the first time since 2002 and went nine months without a title.
But the Swiss superstar took a six-week break after his US Open defeat by world No.1 Novak Djokovic and has returned with a 17-match unbeaten streak.
Federer celebrated a century of singles finals by beating Jo-Wilfried Tsonga 6-3 6-7 6-3 and banked just over £1million.
And the 30-year-old admitted he has returned with renewed confidence which he will carry into next year.
"It's a mental thing," said the winner of 16 Grand Slams. "You can't always be positive out there - it's just too difficult.
"That's where maybe the doubts were just a bit too strong during certain important moments.
"I didn't have those doubts for the remainder of the season, which is what I wanted to get out of my system during this six weeks break, and I was able to do that.
"I've never finished a season so strongly. It gives me a lot of confidence for next year."
Federer overtakes the record he previously held with Ivan Lendl and Pete Sampras - and becomes the oldest man to win the endof-season showdown.