Federer was stunned by Kei Nishikori in the opening group match at the ATP Finals on Sunday, falling into a consecutive defeat.
He brought a crunch meeting with his team of coaches to the Swiss star, and they came to the decision to take a day off to rest.
The move paid dividends as Federer's answer, passing next to Dominic Thiem in his second tire.
He followed the same routine before his victory against Kevin Anderson last night he saw 20 -time The Grand Slam winner proceeds to the Lleyton Hewitt Group at the top of the standings.
Federer will discover his opponent in the semi-final today as the Guga Kuerten Group is approaching.
But the 37 year old will have his feet up waiting to discover his destiny.
"I feel great, I'm very happy to still have energy in the tank. I feel cool, to be honest," said Federer.
"Well, look, everyone does it differently.
" Everyone has coaches and people of different ages that gives you different advice.
"Look, I'm a big fan of holidays, I'm a big fan of free time sometimes, when I go to work, I go hard, I go in the right way, I go professional with my team.
" I did not think to take a day off, actually, after the Nishikori game. "What will we do, where will we go to train?"
"They said:" What about a day off? "
" I said, "Sure, I'm happy for a day Off. It's only if you guys want it."
"Here's how we made the decision quickly. The next day Nishikori, as we realized, made me happy, relaxed, motivated when I come to court, that works. We kept it. I have not exercised [Wednesday]. I doubt that I will practice [Friday].
"I think if I could not train at Center Court, there's no reason to go to another camp, feel a different kind of atmosphere. It's great.
" I can warm myself up with you play with great intensity and I'm ready to go.
"I have played so much of my career, so much this season, especially recently, we do not feel the urge to have At this point everything depends on the games."
Federer was practicing at the Queen & # 39 ; s Club in the west of London before the end of season event.
But he was unhappy with the grass fields because they were several steps towards the harsh court of the O2 Arena in London.