The 34-year-old has glided into the semi-finals, where he will face Swiss compatriot Stan Wawrinka today.
It will be his 10th New York semi-final as the five-time champion targets a record sixth US Open and 18th Grand Slam title.
"For many years I have tried to look at the big picture to hopefully still be playing at a high level at this age," said Federer, who would be the oldest winner of the US Open since Ken Rosewall in 1970.
Federer has not won a major since his seventh Wimbledon title in 2012, but came into the US Open on the back of a seventh Cincinnati title, defeating world number one Novak Djokovic in the final.
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It was his 87th career title and pushed his on-court earnings to almost USD 94 million.
His form in New York has been just as impressive, dropping serve just twice and not yet having lost a set.
Despite his Grand Slam title drought -- the longest of his career -- Federer has not been afraid to keep innovating.
The US Open is only his 13th tournament of the year.
He has also invented a new tactic, the 'SABR' or 'Sneak Attack By Roger,' which is his chip-and-charge on an opponent's second serve.
After his 87-minute quarter-final demolition of Richard Gasquet on Thursday, Federer also said he was sleeping more -- up to 10 hours a day -- to maintain his competitive level.
"I think I have worked on my game moving forward, have been able to take the ball earlier," he said when asked to explain his longevity.
"I've played so well over the last one-and-a-half years. I don't feel like I'm as old as I am. I still feel young."
He has come close to adding to his 17 majors.