Roger Federer
Switzerland's Roger Federer reacts during his Men's singles quarter-final match against Germany's Mischa Zverev, Australian Open, Melbourne, Australia, Jan. 24, 2017. Reuters/Thomas Peter

In his first official tournament since spending six months on the sidelines with a knee injury, Roger Federer will take on compatriot Stan Wawrinka in the semifinals of the Australian Open on Friday. And nobody is more surprised than the Swiss great himself.

“I think now that I'm in the semis, feeling as good as I am, playing as good as I am, that's a huge surprise to me,” Federer said Wednesday after defeating Mischa Zverev in the quarterfinals. “Like I said on [the] court, if someone would have told me I'd play in the semis against Stan, never would I have called that one for me. For Stan, yes, but not for me. I honestly didn't even know a few days ago that he was in my section of the draw or I'm in his section.

“I figured it out eventually that he was playing on my days, but I never really looked in that quarter of the draw because that was just too unrealistic for me.”

Following his absence, Federer went into the tournament seeded 17th – his lowest seeding at a Grand Slam in almost 16 years. It meant the unfamiliar prospect of having to get through two top-10 opponents before even making it to the quarterfinals. But rather than wilt, he passed both tests with flying colors.

First, he blew past former Wimbledon finalist Tomas Berdych in straight sets before going the distance to get the better of fifth seed Kei Nishikori over five sets.

Had he given thought to making it to the quarterfinals, Federer might have expected to have had to take on Andy Murray. But the world No. 1 was shockingly ousted by German Zverev, who Federer, in contrast, brushed aside in 92 minutes.

Suddenly, an 18th Grand Slam title is now in his sights. But his opponent on Friday may also have an eye on his own legacy. Wawrinka did not win his first Grand Slam title until two months shy of his 29th birthday, yet he is now chasing down his fourth. Were he to get it, it would give him one more than Murray.

A champion in Melbourne in 2014, Wawrinka’s place in the final four is certainly less of a surprise than his illustrious compatriot and next opponent. However, the 31-year-old was almost sent packing at the first hurdle, having had to survive a tense five-set tussle with Martin Klizan.

Since then, Wawrinka has been given little undue concern, including when getting the better of Jo-Wilfried Tsonga in straight sets in the quarterfinals. But to go any further he will have to improve on an 18-3 losing record against Federer, which included an emphatic straight-sets defeat in their last Grand Slam meeting, at the same semifinal stage of the 2015 U.S. Open.

“Yeah, it's going to be a great match, for sure,” he said after getting the better of Tsonga. “Last time I think I got killed in U.S. Open. He was playing way better than me, moving really well, really aggressive from the court.

“It's going to be interesting match. He's playing so well since the beginning of the tournament. He had a little bit some hesitation in the two first rounds, but since that he's really flying on the court. It's great to see him back at that level. Hopefully, I can manage to play a great match.”

Prediction: Few could have predicted Federer to have made it this far, but now he is in the semifinals he has a great chance of going all the way to the title. Wawrinka has never beaten Federer on a hard court and the quickness of the courts in Melbourne should suit the elder Swiss. If his body and serve continues to hold up then a place in the final should be his.

Federer in four sets

Match Time: 3:30 a.m. EST
TV Channel: ESPN
Live Stream: Watch ESPN