The beauty about sport is we never know what might happen when we arrive at a stadium or turn on our television.
But one thing comes as close to sporting certainty as anything else we have seen over the past 15 years: Rafael Nadal winning the French Open.
"Some say beating Rafa over five sets on clay is the toughest thing in sport - not just tennis," said seven-time Grand Slam singles champion John McEnroe. "I would agree with that."
Since making his debut as a talented teenager in 2005, Nadal has won a record 13 singles titles at Roland Garros - no player - man or woman - has managed to win as many at the same Grand Slam.
And the 34-year-old Spaniard lifted the Coupe des Mousquetaires yet again on Sunday, beating Serbian top seed Novak Djokovic.
What makes the man nicknamed the 'King of Clay' almost unstoppable on the red dirt?
His Vicious Forehand And Movement
Nadal's numbers at Roland Garros are simply staggering.
As well as extending his record for the most titles, he became the first player to win 100 matches at the clay-court Grand Slam by beating Djokovic.
Not only has Nadal beaten the previous records - he has smashed them.
Borg won six French Open titles between 1974 and 1981, setting a record that stood until it was surpassed by Nadal in 2012.
"I was around the era where I thought I was watching the greatest - I was at the time - Borg. Nadal eclipses him," said McEnroe, a Roland Garros finalist in 1984.
Nadal's main weapon is that vicious, lasso-style forehand which has become his trademark.
That, added to his sharp movement and supreme athleticism, is what makes Nadal great, according to Chang.
"He has the uncanny ability of being able to hit a lot of forehands and move very well on clay," the American, who won Roland Garros as a 17-year-old in 1989, told BBC Sport.
"He knows how to manipulate the angles to build to get people out of position.
"He is very aggressive, although patient when he needs to be, but for the most part if the shot is there he is taking it and going for it.
"He's the one manipulating, making you move and putting you in awkward positions to the point where he has easy cutaways."
'Perfect' Conditions
The clay surface slows the ball down more than grass, enabling Nadal to use his athleticism to construct his points and tee up that famed forehand.
Rafael Nadal in action during the French Open final against Serbia’s Novak Djokovic on October 11, 2020 — Reuters photo
In turn, it helps him hit the ball harder and more accurately, while the hotter summer temperatures in mainland Europe - where the majority of the clay-court season takes place - help Nadal generate more bounce.
It is notable that Nadal's successes in Monte Carlo and Rome, two of the Tour's three clay-court Masters tournaments, outnumber those in Madrid - the third - as the high altitude of the Spanish capital means the ball has less top spin and bounces lower.
"The conditions at Roland Garros suit him perfectly," said Austria's Dominic Thiem after he lost to Nadal in the 2018 final. "It's similar to Monte Carlo, where he also plays amazing.
"Also the court at Roland Garros is very big. We can return very far behind the baseline. That's an advantage to him."
In 2020, the conditions were far from Nadal's liking.
Going into the tournament, Nadal said the colder conditions in an autumnal Paris and a heavier new ball provided him with the "toughest test" he had ever faced at Roland Garros.
Even Djokovic hinted before the match he felt the conditions gave him a "better chance" because Nadal could not get the ball as high.
Yet the Spaniard still won the title without dropping a set.
Two-time French Open champion Jim Courier said he thought the conditions might have actually helped Nadal, particularly in the final against top seed Djokovic.
Nadal played with controlled aggression of the highest level, hitting 31 winners and making just 14 unforced errors.
"Maybe we were thinking about it the wrong way and maybe Rafa was too," said Courier in his position as television analyst for ITV.
"Maybe the slower conditions helped him. Rafa was able to get to the ball and land the blow with so little risk because he has so much spin on the ball.
"The fact he had almost the same amount of winners as Novak did, who was playing so much more risky tennis, and less than a third of the unforced errors was mind-blowing."
Being A Leftie
Nadal is a left-handed player which, in conjunction with his other attributes, is a key part to his success, according to Chang.
"If Rafa was a right-handed player I don't think his game would be quite as effective," said the former world number two.
"Being a leftie means that everything spins the other way.
"The strong forehands always come into a right-handed player's backhand, hooking him off the court, and the inside-out coming back the other way, it is tough to cover."
Growing Up On Clay Courts
Clay is the natural surface for Spanish players, with about 100,000 red-dirt courts across the country - even most small villages have them.
So it is not surprising that Nadal is the latest in a long line of Spanish success - albeit far more sustained than his predecessors - at Roland Garros.
Nadal's 13 wins, plus triumphs for Sergi Bruguera (two), Carlos Moya, Albert Costa and Juan Carlos Ferrero, means the nation has accounted for 18 of the past 25 male champions.
"Roland Garros has always been the most special tournament for us," said Joan Solsona, a Spanish tennis journalist who has worked for daily sports newspaper Marca since 1998.
"So it affects the way you prepare as a tennis player - you want to be good on clay. Playing and learning on clay is natural for Spanish people."
Majorca-born Nadal first stepped on to clay aged four, starting to practise at his local tennis club in Manacor with his uncle Toni - the man who developed and coached him until retiring last year.
"Nadal was from a small town of 40,000 people and his local club had six or seven clay courts," added Solsona.
"We are lucky because Spain is a sunny country and this has a big effect. The clay courts stay in good condition in the good weather and means you can practise on them all year round because of the weather.
"We're also advised that playing on clay is the best surface for children to learn on because it is easier to move on and means they don't get injured as much.
"So Rafa started moving on clay from a young age and it shows."
How Do You Beat Him?
Nadal has only lost twice at Roland Garros - he pulled out before his last-32 match against fellow Spaniard Marcel Granollers in 2016 with a wrist injury.
Long-time rival Djokovic was the last person to actually beat him on court, winning in straight sets in their 2015 quarter-final.
Djokovic went into the match as the favourite, being the world number one and on a 26-match winning streak.
Nadal's first defeat at Roland Garros, however, was a seismic shock.
A last-16 victory in 2009 earned Robin Soderling, an unheralded Swede who had never previously checked into the second week of a Grand Slam, a place in the sport's history books.
"On that day everything worked for me," Soderling told BBC World Service.
"You have to be extremely aggressive. There is no other way of beating him on clay.
"You have to play a little bit flatter than you usually do, play close to the baseline and take your chances.
"You need to play with smaller margins and take some risks because no-one will beat him staying two metres from the baseline and beating him on his own terms. You have to take the initiative."