In the 2005 French Open final, late in the fourth set, Mariano Puerta has three set points to tie the match. Uncle Toni is stoic in the stands; the boy in white bandana and green sleeveless top is sweaty; the commentator is certain. "It's all going pear-shaped fast at the moment for Rafa Nadal."

The commentator is forgiven, he doesn't know Nadal yet. Doesn't know that he will save every set point. Doesn't know that when Puerta hits a delicate drop shot at break point that this Spaniard in pirate pants will storm the net and get to the ball. He will win the point and then the Open.

Later Puerta will say: "I wonder how he was able to get that ball?"

Thirteen years and 10 French titles later we're still asking. Rhetorically now. Then he's 19, now he's 31 and after pain and despair and rehabilitation, much has changed and yet nothing has.

Nadal is still the high priest of perseverance. He contests every single point as if it is a championship in itself. He pursues every single ball as if his life's work hinges on this particular effort. He constructs bewildering shots because his inner voice can never convince him that a ball is unreachable. We've known this for years and still it's staggering.

That is what we learnt on Sunday. There is evidently no Spanish word for "enough". We learnt also that Roger Federer is smarter than we think. Stay in Basel during the French, he told himself, best to let another Swiss suffer.

We learnt that we should have listened more closely to Puerta in 2005, when he said of Nadal: "We are talking about someone who is going to write a page in the history of tennis. I think he's going to do beautiful things in tennis... I think he has the mental strength to beat records."

We learnt, on Sunday and in January, that Nadal and Federer don't just win matches, they stretch the idea of excellence and test imaginations. An Australian Open for a 35-year-old four-kid father and a 10th French for a fellow with body parts whose warranty has run out? Had you forecast that a decade ago, you'd have made Nostradamus seem like an idle tea-leaf reader.

We learnt that comparing these men and bracketing them is premature because their athletic CVs are epic but incomplete. Every latest act seems to be their greatest act. If you must label them, then just put them with Michael Phelps and Usain Bolt in the folder marked "Damn, Never Going To See Again". Well, not if you're over 40.

We learnt on Sunday that Nadal has returned to what he used to be on clay, a breaker more of the spirit than merely the serve. If Stan Wawrinka requires solace he can have a drink with Guillermo Coria, who when beaten in the Rome final in 2005, just before La Decima began, said of Nadal: "I fought, I gave everything I had... He was always responding with incredible shots on lines."

Sport is best played with the free mind but Nadal at the Open suffocated rivals into self-doubt: Where is the space to hit? How close to the line must I hit? Why does his side of the court look smaller? How many times must I end a point? I know I should hit to his weakness but can you tell me where is it? Is life fair?

It's like trying to solve a puzzle while multiple conversations are going on in your head and as Mats Wilander, thrice a French champion, told the BBC: "You get out there and realise, 'Hold on a second, I don't even know how to win points, let alone sets'." Federer, at his best, can leave a player embarrassed, but Nadal leaves them stricken.

We learnt, again, that Nadal is whom you want to present to your son, or niece, or school team, as proof of the simple, durable qualities of sport. The ones about honesty, work ethic, patience. The ones about wearing defeat but not wilting, for before this year began his record at the previous six Slams were second round, third round, first round, third round, no show, fourth round. The ones about always improving, for he's sharpened his serve and added iron to his backhand. Imagine at 31 the faith this took, the will it required.

We learnt that champions who last through the years offer us two unique views of themselves and it's hard to say which one is more intriguing: Do you like the young, invincible Rafa or this mended, resurrected one? For me it's the second version because it's the more hopeful and human one.

We learnt things on Sunday that we knew of before, but we needed reminding of anyway. We learnt that his knees are more resilient than we once feared and that this particular Paris court is his version of Superman's phone booth. No cape, but always in flight.

We learnt, finally, that the French is where he first began to cry. "For the first time, I cried after winning a match," he said after the 2005 final and it seems he has never stopped since. But as the tears arrive he always falls on his back in relief and it is an appropriate act because when he rises he is coated in the dust that defines him. An exhausted painter streaked with the dominant colour of his masterpiece.