In an astonishing reversal of fortunes, the 33-year-old, written off as a relic of the game when he slipped to a fourth round loss to Tommy Robredo in 2013, is perfectly positioned to win a staggering 18th major at the season's concluding Grand Slam event which starts Monday.
Buoyed by claiming a sixth Cincinnati title and his 80th career crown, the Swiss is revelling in the twilight of his career just a year after it was being consumed by darkness.
That last-16 loss to Robredo meant it was the first year since 2002 that he had failed to make a Grand Slam final.
The defeat also marked the first time in 10 years that he hadn't made at least the last-eight at Flushing Meadows.
Suddenly, his five consecutive US Open titles from 2004-2008 appeared a detail in history and his 17th and most recent major success -- the 2012 Wimbledon title -- looked certain to be his last.
But the Swiss never doubted his ability to remain a force in the sport and he goes into his 15th US Open with his unwavering confidence justified.
There were hints of a revival at Wimbledon in July where he was defeated in five sets by world number one Novak Djokovic.
Since then, he has been runner-up at Toronto and champion in Cincinnati.
"I come in with great confidence," said Federer, chasing a record sixth title in New York and where he will be playing in a 64th consecutive Grand Slam.
"I know my game is where I want it to be. It's about just keeping that level up right now."
Meanwhile, his fellow members of the "Big Four" are slipping and sliding.
Djokovic, the 2011 champion, heads into the tournament with two dispiriting third round losses in Toronto and Cincinnati with the 27-year-old Serb, recently married, having to bat back accusations that he is distracted by impending fatherhood.
"Just many, many, many things are not clicking," said Djokovic.
"I'm not feeling very comfortable on the court," the Serb said.
"Obviously I want to peak in New York," he said.
"I expect more from myself, but I have to keep on going.
"A Grand Slam is coming up, and that's where I want to do well."
Despite his recent troubles, Djokovic, whose second Wimbledon title took his majors haul to seven, will still be the big favourite in New York having reached the final in the last four years.
Furthermore, his record at all the majors is impressive -- the last time he failed to make at least the quarter-finals of a Grand Slam was at the 2009 French Open.
The odds on Djokovic and Federer meeting in the September 8th final were shortened on Monday when defending champion Rafael Nadal was forced to withdraw with a right wrist injury.
Andy Murray, the 2012 champion, has not reached a final of any description since his historic 2013 Wimbledon triumph, prompting many to believe that the Scot's work is done.
Now down at nine in the world, the 27-year-old has not got beyond the quarterfinals of any tournament since his morale-sapping semifinal loss to Nadal at the French Open where the Spaniard allowed him just six games.
With 2009 champion Juan Martin del Potro still sidelined by injury, the much-vaunted next generation will get another opportunity to shine.
Canada's Milos Raonic, the world number six, was a semifinalist at Wimbledon and Cincinnati where he was swept aside in straight sets on both occasions by Federer who made him look the one-dimensional big-server many in the game believe him to be.
Fellow 23-year-old Grigor Dimitrov, the world number eight, has three titles to his name in 2014 but lost out to Djokovic in the Wimbledon semifinals.
More frustratingly, the Bulgarian boyfriend of Maria Sharapova, has yet to win a match in three visits to the US Open.