Roger Federer revealed he had overcome some mental demons after defeating Jo-Wilfried Tsonga to clinch a record sixth title at the season-ending Barclays ATP World Tour Finals on Sunday.
The 6-3 6-7 (6/8) 6-3 victory took Federer's record since the US Open to 17 wins and no defeats, earning him titles in Basle and Paris as well as at London's O2 Arena. The 30-year-old declared the record one of his biggest achievements, but it was the manner of his victory that meant the most.
Federer has made an unwelcome habit of losing close matches this season, most notably a Wimbledon quarter-final against Tsonga and his US Open semi-final defeat by Novak Djokovic. In both of those matches he led by two sets, a position from which he had never before lost in a grand slam, and he revealed the long break he took after Flushing Meadows was partly to address those nagging doubts, saying: "I think it's a mental thing, yes."
He added: "Not only. Sometimes it's also the player playing better than you. Jo played better than me at Wimbledon. Maybe not much, but enough just to come through.
"Same as Rafa (Nadal) at the French Open in the final, Novak in the semis of the US Open. It's fine to respect that. But I feel when it happens that often, I do have to question myself that maybe I did something wrong.
"I think I'm mentally good right now. That was also one of the reasons why I did take some time off, to actually think it through, get into the right mental mindset. There is a lot of time that goes by out on tour, during a match, you're just trying to stay positive, but 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 wanted to get that out of my system during the six-week break, and I was able to do that."
Federer conceded the US Open loss, in which he also held two match points on his own serve in the final set only for Djokovic to turn things round in a flash, was particularly hard to take.
"It was one that hurt," he said. "It was one that makes you wonder, 'How in the world can I end up losing this match?' But Novak had such great momentum going this season, you just felt like it was his season.
"But to bounce back and not lose a match from that moment on I think shows, again, how tough I am, the right decisions I can take. I also lost to Jo twice in a row at Wimbledon and in Montreal. Now I beat him four straight times. These are the kinds of reactions I expect from myself. So to come through and prove it to myself was a great feeling."