The 34-year-old Swiss believes napping, as well as the routine of practice and gym work, is just as crucial as he enters his 10th New York semi-final and 20th career clash against his compatriot.
He is so fond of sleep that Federer will look to get in as much as 10 hours a day before Friday's semi-final, where the winner will face either world number one Novak Djokovic or defending champion Marin Cilic in Sunday's championship match.
"I make sure I sleep enough, as well. Like when I went to bed after the John Isner match (in the fourth round) it got quite late and I couldn't sleep quite as much as I wanted to.
"Because I believe it's really the sleep that gives you energy again down the road. That's why the next two days are very important for me in terms of sleeping."
If the approach for such a high-stakes clash seems risky, then Federer is showing no signs of nerves as he moves two wins from an 18th major and his first in more than three years.
On Wednesday, he blitzed French 12th seed Richard Gasquet in just 87 minutes, firing 50 winners, 16 aces and facing just a single break point.
Furthermore, he has a 16-3 record against Wawrinka.
He may have lost their most recent clash in the French Open quarter-finals as Wawrinka swept to the title, but Federer's three defeats have all come on clay.
"I think a lot comes through practice for Stan, because he's worked very hard throughout his career," said Federer in praise of his Davis Cup winning teammate.
"I think only once when he really started to break through and he had some big wins."
Wawrinka believes he is now the equal of Federer, something he did not quite believe before he won his first major at the 2014 Australian Open.