You know a rivalry is intense when there's an actual word for it. The 'Fedal' rivalry between Roger Federer and Rafael Nadal first started in March 2004 on the hard courts of Miami and to date there have been 34 editions of it, with Nadal winning 23 of them.
There have been concerns over the last couple of years that there might not be a 35th edition of it as Nadal's long-term knee and wrist troubles and Federer's back operation (not to mention age) threatened to bring to a close the careers of both players.
But there will be. And on one of the biggest stages of them all. Early exits at the 2017 Australian Open of Andy Murray and Novak Djokovic paved the way for the two greats to meet in a Grand Slam final once again. Nadal trades on Betfair as the 1.824/5 favourite with Federer at 2.26/5 and that's understandable given the Spaniard's far superior general Head-to-Head record and better record on hard courts, too (9-7).
As we wait for Sunday's showdown, let's remind ourselves of five of the best.
1) Gladiators slug it out (Rome Masters Final 2006)
Things weren't looking good for Federer when he went into the Rome Masters final. He'd lost four of his first five encounters against Nadal, who was on 52 wins on clay and needing one more to equal Guillermo Vila's record of 53 straight clay wins.
This match may not have made everyone's top five because it wasn't at a Grand Slam. But in those days the Masters Finals were played over five sets and having been lucky enough to be there, I can tell you the quality of the tennis was as good as anything I've seen from them.
Perhaps more than any other, Federer will look back and wonder how he lost this one. He took the first set, was 4-1 up in the fifth set, had two match points on Nadal's serve deep in the fifth and led 5-3 in the final set tie-breaker. But lose it he did.
Lesson of the day: With Nadal it's not over till it's over.
2) Federer makes mincemeat of Nadal in Hamburg (Hamburg Masters 2007 Final)
At first glance there was nothing particularly remarkable about this Federer win over Rafael Nadal in the final of the 2007 Hamburg Masters. But Federer's 2-6, 6-2, 6-0 win was very significant. Not only was it Federer's first-ever win over Nadal on clay but it also ended Nadal's 81-match winning streak on clay.
After the match Federer said he'd finally worked out how to beat his rival on clay. But had he? A few weeks later it was business as usual as Nadal beat him in four at the French Open.
Lesson of the day: Beating Nadal on clay wasn't impossible. It was just very, very difficult.
3) Federer calls the shots on Centre Court (Wimbledon 2006 final)
If there was one thing Roger Federer wasn't going to stand for back in 2006, it was to lose to Nadal on grass. He was the King of Wimbledon, having won the last three editions. He was the better server, the better mover, the better player at the net.
This was their first-ever meeting on grass and Federer's greater pedigree on the green stuff was obvious for all to see. The Swiss champ won 6-0, 7-6, 6-7, 6-3 and Nadal would have to adapt his game to the slippery lawns of SW19 if he was to ever win this one.
Lesson of the day: Don't mess with Federer in south-west London.
4) Nadal closes the deal in the dark (Wimbledon Final 2008)
In 2007 Federer beat Nadal at Wimbledon again but things were getting closer. On that occasion he needed five sets.
But in 2008 Nadal went one better. Considered by some as the greatest tennis match of all time, it had a bit of everything. The match started 35 minutes late because of rain, Nadal received a time violation warning for taking too long on serve, there was a rain delay of 80 minutes towards the end of the third set and a further rain delay at the end of the fourth, by which time Federer had battled back from 0-2 to 2-2 in sets.
By the time they came back for the fifth, they were playing in near darkness. Nadal eventually won 9-7 in the fifth. 'It was so dark I almost couldn't see who I was playing.' Federer said after the match.
Lesson of the day: Nadal has the better eyesight of the two
5) Nadal on the up Down Under (Australian Open Final 2009)
What may seem impossible to mere mortals is very possible when Rafa Nadal is involved. Just two days previously, he'd spent over five hours on court beating compatriot Fernando Verdasco. Federer meanwhile had made light work of Andy Roddick in the semi, winning in straight sets.
It was also Federer's ninth hard court Grand Slam final and he'd won the lot of them before this one. Oh yeah, it was also Nadal's first-ever hard court Grand Slam final.
Odds stacked against you? No problem. Nadal won it in five, in the process becoming the first Spanish player to win Down Under.
Lesson of the day: Nadal is the real deal on any surface
Check out tennis columnist Dan Weston's betting preview of the final