The Swiss will rarely have had to fight harder than he did to subdue Stan Wawrinka in the Australian Open semi-final and become the oldest man to reach a grand slam final since 1974, yet he did so with grace and panache

It was as nailed-on that there would be a Swiss player in the men’s final of the 2017 Australian Open on Sunday as it was that an American would win the women’s title on Saturday. The odds that their combined ages would be at least 70 were a little tougher to see at the start of the fortnight but it crystallized into stunning reality here on the 11th day of a tournament that has had more twists than the Melbourne Grand Prix.

A few hours after Serena Williams, 35, joined her 36-year-old sister, Venus, in the women’s final by trouncing the 34-year-old Mirjana Lucic-Baroni, Federer, 35, somehow conjured some more retro magic to beat Stan Wawrinka, a mere 31, for the 19th time in 22 matches. His bete noire, Rafael Nadal, plays Grigor Dimitrov, his young doppelganger, in the second semi-final on Friday.

Roger Federer beats Stan Wawrinka to reach Australian Open final Read more

In so many ways, what Federer has done the past fortnight – and what he might do in his 100th match here, on Sunday – is beyond believable. When he forced a final weary shot out of his friend after a few ticks over three hours to win 7-5, 6-3, 1-6, 4-6, 6-3, Federer became the oldest man to reach the final of any major since Ken Rosewall at the 1974 US Open, when the Australian was 39. And the Swiss wizard has done it after six months off the Tour to recover from knee surgery. If he played on one leg, he could not amaze us much more.

Federer took a medical timeout between the fourth and fifth sets and the faithful must have wondered if maybe he had come back too soon. When he returned to the court, he allayed their fears, battered Wawrinka and they rose to acclaim him as of old. They always believed he would.

“I’ve had a leg thing going on for the week,” he said courtside. “I felt it from the second game of the match. I never take injury timeouts. I hope Stan wasn’t mad.” Wawrinka took one of his own, earlier. And he didn’t look too mad when they embraced at the net.

He was pressed to be more specific about the injury. “If you go off the court, the treatment is further up the leg. It’s still the leg, right?” And that, of course, went down like the best joke of the year.

He added: “I never, ever in my wildest dreams thought I’d be coming this far in Australia.” There were a few present who always held that dream close.

Some people came to watch a tennis match on Thursday night. But it was easy to see why a lot of them were here for a religious experience, in adoration of the god they call Roger. It was as if the Rod Laver Arena was not big enough to house their devotion. He did not disappoint, although he did wobble.

Roger Federer: in numbers 1 – the last time he was ranked world No1 was 29 October 2012, with the first time being in February 2004

4 – the number of times he has lifted the trophy in Australia; the years were 2004, 2006, 2007 and 2010 17 – his number of grand slam titles, which is also the all-time record 28 – his number of grand slam final appearances 63 – his first-serve percentage in this year's tournament before the final

$98,830,825 – prize money he has earned during his career, singles and doubles combined

For a man who has the dress sense of your grandfather, he is to millions of tennis fans the coolest guy in sport. Just the coolest guy all round, really. He can do no wrong, even when he does, although he kept his unforced errors to a manageable 49. Novak Djokovic won a match here last year hitting a hundred of them.

But Federer’s mistakes are mere accidents that spring from his daring. It does not require blind faith to appreciate the special player that he has been, still is, and, for as long as he chooses or until someone lets the tyres down on his wheelchair, will continue to be. It is not just that he plays and looks magnificent carving the air with his racket, going for the winning shot whenever it presents itself. He also brings a panoply of gifts to his sport that have little to do with tennis.

Federer shakes more hands and hugs more babies than a politician – and what a good one he might make. Then again, diplomacy, correctness and an obsession with honesty have always underpinned his excellence, so maybe he would be a lousy one.

Wawrinka is earthier and built of different material. Brad Gilbert calls him “the Stanimal” for a reason. On Thursday, he growled all the way to the end.

Earlier they walked from the locker room together, Wawrinka a couple of yards and four years behind his compatriot, perhaps looking for the merest hint of physical slippage, but more likely lost in thought about his gameplan.

How different things might have been, though. Before the match, the governor general, Peter Cosgrove, presented the nation’s highest honour, the Companion of the Order of Australia, to Rod Laver in his eponymous arena. He has a statue outside too. The old boy, who has lived in the United States for many years, remains immensely proud of the country he was born in 78 years ago and comes home as often as he can.

If Federer’s parents had gone through with plans to emigrate to Australia when he was 13 the explosion of applause for him when he reached the 28th slam final of his career, and his sixth in Melbourne, would have been heard in Perth – Scotland, that is.

There is, nevertheless, a lot of Australia in Federer. One of his earliest mentors was the South Australian Peter Carter, whose death in a 2002 car accident devastated him. His tears after winning here in the past have roots deeper than an attachment to victory.

Facebook Twitter Pinterest Roger Federer stretches to return against Stanislas Wawrinka. Photograph: Saeed Khan/AFP/Getty Images

He has said more than once that he learned respect and a work ethic from Carter, whose family he seeks out on his annual visits. When he was going through a trough a few years ago, he joked that he had only got them tickets for the quarter-final as he was not sure he would progress much further.

It is interesting to speculate what Federer the Australian would have become. As a precocious teenager, he was already moving – loudly and some times petulantly, it has to be said – towards a career in tennis. Might he also have tried cricket? He does like the game and almost certainly would have been a fine batsman. His maternal grandfather was a big noise in the Northern Transvaal Cricket Union.

Roger Federer beats Stan Wawrinka in five sets to reach Australian Open final – as it happened Read more

But Switzerland remained Roger’s home. It is also his haven. For years he lived in quiet, conservative Bottmingen in Basel-Land. In 2014, he and Mirka and their four children moved into a £6.5m mansion 70 miles away in Wollerau on the shores of Lake Zurich. Glass surrounds flood the residence with light, as if he did not generate enough himself.

All of that was a long way from the battlefield in Melbourne. Federer had to fight harder than at any time since his return to subdue Wawrinka. When he dropped serve in the third set to go 1-4 down, it was the first time he had been broken since the second set against Mischa Zverev. When Wawrinka broke him again, anxiety spread in the congregation. When Stan served out the set to love, mild panic set in. Federer lost the fourth set too. The fans held their breath – then they voiced their wholesale delight when he slowly but inexorably worked his way to the finish line.

Federer came from behind to beat Kei Nishikori in five sets in the fourth round. This was the 46th five-setter of his career, his second in four days. Wawrinka has played 45. One thing is certain. There will be one tired Swiss on court on Sunday.