A straight sets near "double bagel" of Andy Murray in the group matches -- not to mention his saving of four match points in his epic semifinal against fellow Swiss Stanislas Wawrinka -- was proof positive of the 33-year-old's renaissance.
He also beat world No.1 Djokovic on the way to winning the Masters 1000 event in Shanghai and claimed his fifth title of the year in his hometown event in Basel, the perfect buildup to the year-end showpiece in London.
Federer told CNN that his performances in 2013, when he slipped down the rankings to seventh as a result of injury and a loss of form, had left even him with doubts he could return to his best.
"Things were difficult mid-year last year," said the 17-time grand slam winner.
"It was a hard year, a long year. I had to put in a lot of effort mentally and physically to get back in shape and find the right solution, how I was going to get back."
Federer parted company with his coach of three years Paul Annacone in his quest to rediscover his best form and replaced him with former grand slam legend Stefan Edberg.
Not only that, he switched to a much bigger framed racket -- something of a gamble so late in his career.
But with the year only a few days old, Federer reached the final of the Brisbane International, losing to Lleyton Hewitt, and the semifinals at the Australian Open where he was beaten by his old rival Rafael Nadal.
"This year, everything has been really good. Right at the beginning of the year, in Australia," recalled Federer. "I played very well in Brisbane and in Melbourne.
"That was actually quite a surprise for me, because I thought it was going to take until March or April until I was going to find my best game.
"But it came earlier and in the process, I was able to move up the rankings quicker," he revealed.
That progression quickened with titles in Dubai and Halle, backed up by reaching the final of Masters 1000 events in Indian Wells and Monte Carlo.
It left Federer in fine fettle as he headed into his beloved Wimbledon and with a real prospect of adding to his record number of grand slam singles titles.
Impressive play saw him reach his 25th grand slam final, but Djokovic stood in his way.
It was an epic encounter, Federer so close to causing an upset in a five-set final, but he can now reflect with pride on his achievement.
"I think Wimbledon was definitely a highlight -- getting to the final and getting as close as I did to Djokovic," he believes.
"That, to me, cemented that I was literally back -- back maybe where I belong and back where I wanted to be."
Federer also looked set for more grand slam glory at the U.S. Open, until he was surprisingly beaten by eventual winner Marin Cilic.
A lesser player might have suffered an adverse reaction to that defeat, but Federer was undaunted and has shown improved form in the closing months of the year.
"I've been able to really shift gears -- and I've had a great finish to the season so far," he said. "And the next thing you know, I'm playing for world No.1, which I quite honestly can't believe."
Federer's hopes of the top ranking were ended when Djokovic beat Tomas Berdych in group play at the ATP World Tour Finals, but he still has one further milestone to contemplate.
Paired with Australian Open champion Stanislas Wawrinka, Federer has lifted Switzerland into the final of the Davis Cup for the first time.
France will provide the opposition in Lille from Friday, with Federer hoping the minor back problem he sustained -- ironically in beating Wawrinka in a three-set epic at the ATP World Tour Finals -- will clear up in time.
A Swiss triumph would cap a remarkable year for Federer, who is already looking towards 2015.
With Rafael Nadal sidelined by injury and illness and Murray unable to match his heroics of 2012 and 2013, the way looks clear for the current top two to dominate.
But Federer is also wary of the new wave of talent that made their mark this year.
"We definitely have the next wave of generation coming through," he considers.
"With Nishikori, Raonic, Cilic, Dimitrov -- there's a few guys there. The younger guys are pushing up as well -- the guys between 17 and 21, right now.
"I think we'll see some big challenges coming from that generation in the next two years."
Federer is particularly impressed by Kei Nishikori, who beat Djokovic in the semifinals of the U.S. Open and pushed him hard in the semifinals in London last week.
"I've known Nishikori since he was 17 years old, and I've always been impressed by how he carries himself, how he handles pressure, how well he can play and how talented he is," said Federer of the Japanese rising star.
"So I think for Asia, it's a big deal, a big win, because we haven't had a great Asian player in some time now. "
Federer is also optimistic about the future of his sport as heads into the autumn of his remarkable career.
"I think the tennis tour is doing very well, record numbers in attendance, and facilities being upgraded as we speak, so I think it's really, really good times for tennis right now."
When Federer does decide to hang up his racket the Tour will lose its star attraction.
But, based on his 2014 appearances, that moment is still some way off.