Federer still plays for the love of these stages and circumstances. Still yearns for more trophies, too. Down to his very last gasp, time and again, against someone a decade younger, 100th-ranked American Tennys Sandgren, Federer somehow pulled off a memorable comeback to reach the Australian Open semifinals for the 15th time.

Despite all sorts of signs he was not quite himself for much of the match, Federer beat the biceps-baring, hard-hitting, court-covering Sandgren 6-3, 2-6, 2-6, 7-6 (8), 6-3 today in a rollicking quarterfinal that appeared to be over long before it truly was.

“For the most time there, I thought that was it. Of course, there’s little sparkles where maybe not. Then you’re like, ‘No, it IS over,'” said Federer, who only once before had won after facing as many as seven match points, equaling his personal best from all the way back in 2003.

He said afterward that it had been his groin muscle that was the problem and he couldn’t be certain whether he would be fully recovered for his next match. That will come against defending champion Novak Djokovic, who overwhelmed No. 32 Milos Raonic 6-4, 6-3, 7-6 (1) to improve to 10-0 against the 2016 Wimbledon runner-up.