As if we didn't already know the 13-year-old rivalry between Roger Federer and Rafael Nadal achieved legend status long ago, the tournament media office at Indian Wells decided to use Roman numerals -- XXXVI -- to tout Federer and Nadal's fourth-round match Wednesday (8 p.m. ET on ESPN3 and the ESPN App) at the BNP Paribas Open, the 36th showdown of their remarkable careers. And the grandiose touch fits.

After a 2016 season that was cut short for both Nadal and Federer because of injuries, it took their Australian Open final in January, which no one saw coming, to return every meeting they have now to a must-see occasion, not just another sentimental journey. Their five-set epic in Melbourne was that reaffirming -- even for them -- because it reinvigorated their rivalry and re-established both of them as serious contenders for any title on tour, even the Slams.

And that wasn't a given for either of them when 2017 started.

"[It] was a moment that we will remember, something that's going to be part of the history of our sport," Nadal said earlier this week at Indian Wells, even though the loss deprived him of a 15th Grand Slam title.

Federer, who has won a men's record 18 majors, says he places the victory among the most cherished of his career.

Despite losing his last match against Roger Federer, Rafael Nadal still leads the rivalry by a commanding 23-12 margin. Clive Brunskill/Getty Images

"It's in the top five," Federer said Monday. "I don't know if it beats my first one because the first one, it was a dream come true. So that maybe beats everything. ... This one now, after the comeback and the [knee] injury, it was by far the biggest surprise."

At 35, Federer wasn't sure how he would come back from a knee injury that required the first surgery of his career. Nadal, who battled a left wrist injury much of last year, wasn't sure whether he'd return to his former level, either.

He was only 17 the first time he and Federer played, and by then the 22-year-old Federer was ranked No. 1 and the established front-runner. But in a sign of things to come, Nadal upset Federer that day in the third round of the 2004 Miami Masters 6-3, 6-3. Nearly two decades later, he still leads their rivalry 23-12. And while Nadal wasn't all that keen this week about revisiting his loss to Federer six weeks ago in Australia -- "We talked enough," Nadal said -- he was happy to revisit their initial match.

"I went on court [with] nothing to lose," Nadal said. "A lot of motivation to play against the No. 1. In that moment, I was 17. And for me to play against Roger, it didn't matter that it was in that early round. I don't feel it was unlucky for me. It was a beautiful match, and I tried to go out on court and enjoy it and fight for it."

The only downbeat note about Wednesday's meeting is it is happening so early in the tournament because the 10th-ranked Federer and seventh-ranked Nadal are still rebuilding their world rankings. A remarkable 31 of their 35 prior meetings came in the semis or finals of tournaments. But thanks to an uncommonly tough draw, the survivor of Wednesday's match will get the Novak Djokovic-Nick Kyrgios winner in the quarterfinals.

But neither Federer nor Nadal dare to look even that far ahead.

Federer's news conferences this week have been even more reflective and insightful than usual. He's talked a lot about how determined he is to live in the moment and enjoy everything about the gloaming of his career. He's sounded like a man who's not at all content with all he's done, just extremely gratified and proud. And he doesn't deny beating Nadal in Australia has had a lot to do with it.

"I think it was a beautiful thing," Federer said. "I think I should play very relaxed this year, not just here, not just in Miami, not just in Dubai, wherever I'm going to go. I really hope I can play with this lightness, this freshness throughout, because I worked so hard to get to 18 the last five years. It's not always been easy, especially with injuries and losing some tough matches. But I did have good moments, too, you know. ... It was just that I couldn't get a Slam because of Novak, mostly. So I'm happy I finally got it."

Nadal is content with how he is playing, too, even though his uncle Toni Nadal, the only coach he's ever had, announced a few weeks ago that he would no longer travel with him on tour now that Rafa had chosen to add Carlos Moya to his coaching team. While Nadal insists he and his uncle remain on good terms, at least a bit of him must want to prove the rare change in his team will be a good decision. Resuming his mastery of Federer is the best way to start.

"It's exciting for both of us that we're still there and we're still fighting for important events," Nadal said.