Novak Djokovic and Rafael Nadal share the most enduring grand slam rivalry in professional tennis history.
They are the only two men to have clashed in all four major finals in the open era and are preparing for the 44th instalment of their decade-long series.
But the stakes have rarely been higher as the all-time giants of the game prepare for a French Open quarter-final for the ages on Wednesday.
Djokovic, the world No.1 and top seed, must win to keep alive his dream of following Nadal, Roger Federer, Andre Agassi and Rod Laver to become only the fifth man in the modern era to complete a career grand slam.
Nadal, the undisputed king of clay, is striving to become the first man in history to win the same slam 10 times, a colossal feat unlikely ever to be matched.
After enduring a wretched 12 months battling injury, illness and self doubt, the Spaniard is, by his legendary standards, seeded a lowly sixth in 2015 and playing down his chances.
By contrast, four crushing straight-sets wins have taken his unbeaten streak to 26 matches since losing to Federer in February and fuelled Djokovic’s belief that now is finally his time to reign in the French capital.
Nothing, though, can mask Nadal’s mastery over Djokovic at Roland Garros.
Six times the Majorcan has shattered the Serb’s title hopes in Paris, most painfully in 2012 when Djokovic had conquered Nadal in the Wimbledon, US Open and Australian Open finals to stand on the verge of a rare grand slam sweep heading into the title match.
Nadal not only won, but then took the pair’s 2013 semi-final and 2014 final.
All up, he heads Djokovic 9-3 in best-of-five-set grand slam meetings.
The last time Djokovic denied Nadal at a slam, it took the Serb five hours and 54 minutes in their record-setting 2012 Australian Open final.
The 14-times major champion enters the latest clash – their earliest at a grand slam since the very first of their career meetings back in 2006 in Paris – having extended his decade-long Roland Garros record to 70 wins and just one defeat.
“It’s the biggest challenge I can have on clay,” Djokovic said after routing France’s Richard Gasquet 6-1 6-2 6-3 in a fourth-round cakewalk on Monday.
“Playing him here and playing him in any other tournament is completely different.
“The conditions are very suited to his style of game. He loves playing on Court Philippe Chatrier.
“I am trying to keep my routine the same and not give so much importance to the match. I know what to do, I know what’s expected of me.”
Despite his dominant record, Nadal is happy to play the underdog role this time around in a quarter-final being played on his 29th birthday.
“He’s the world No.1 and is having a great season. It’ll be a complicated match,” Nadal said after dropping his first set of the tournament in a 6-3 6-1 5-7 6-2 fourth-round win over the United States’ Jack Sock.
“To have any chance against him, I have to play my real best tennis.”
1-NOVAK DJOKOVIC (SRB) trails 6-RAFAEL NADAL (ESP) 23-20
Nadal 9-3 in grand slam matches
2014 French Open, clay, F, Nadal 3-6 7-5 6-2 6-4
2013 US Open, hard, F, Nadal 6-2 3-6 6-4 6-1
2013 French Open, clay, SF, Nadal 6-4 3-6 6-1 6-7 (3-7) 9-7
2012 French Open, clay, F, Nadal 6-4 6-3 2-6 7-5
2012 Australian Open, hard, F, Djokovic 5-7 6-4 6-2 6-7 (5-7) 7-5
2011 US Open, hard, F, Djokovic 6-2 6-4 6-7 (3-7) 6-1
2011 Wimbledon, grass, F, Djokovic 6-4 6-1 1-6 6-3
2010 US Open, hard, F, Nadal 6-4 5-7 6-4 6-2
2008 French Open, clay, SF, Nadal 6-4 6-2 7-6 (7-3)
2007 Wimbledon, grass, SF, Nadal 3-6 6-1 4-1 – retired
2007 French Open, clay, SF, Nadal 7-5 6-4 6-2
2006 French Open, clay, QF, Nadal 6-4 6-4 – retired
NOVAK DJOKOVIC (SRB)
Plays: right-handed (two-handed backhand)
Career prize money: $US78,397,032 ($A103.06 million)
Career titles: 53
Grand slam titles: 8 (Australian Open 2008, 2011-2013, 2015; Wimbledon 2011, 2014; US Open 2011)
French Open win-loss record: 46-10
Best French Open performances: finalist 2012, 2014
RAFAEL NADAL (ESP)
Plays: left-handed (two-handed backhand)
Career prize money: $US72,745,277 ($A91.90 million)
Career titles: 65
Grand slam titles: 14 (Australian Open 2009; French Open 2005-08, 2010-14; Wimbledon 2008, 2010; US Open 2010, 2013)
French Open win-loss record: 70-1
Best French Open performances: champion 2005-08, 2010-14