Perhaps the most important fact that Roger Federer and his wise old coach Tony Roche have taken aboard about this afternoon's Wimbledon men's final opponent, Rafael Nadal, is how quickly he learns. Not his speed, his athleticism, his confidence, his improvisational genius; they are already painfully aware of those. But how quickly he learns.
In six matches over the past dozen days Rafa has learned how to adapt his biff-bang, run-till-you-drop clay-court game to the more subtle demands of grass, and in case anybody harbours doubts about the lad's learning speed, just listen to his media conferences and marvel at how rapidly he has moved from pidgin English to the ability to understand virtually every question, with the exception of the most obtuse American ones, and to compose his replies intelligently and frankly. Why, he was even holding his own in banter with John McEnroe on television on Friday night.
He has even started to bellow "C'mon", the tour's standard yell of self-encouragement, rather than its Spanish version, "Vamos", though the heels of his tennis shoes still bear the insignia "Vamos" on the left one and "Rafa" on the right.
So, then, the grass-court L-plates have been discarded and this incredible 20-year-old from Majorca prepares to challenge someone who is going for his fourth straight Wimbledon, attempting to tear from Federer's grasp the gold pot the Swiss is, with reason, starting to regard as personal property.
Can he do it? Marcos Baghdatis, the engaging Cypriot 21-year-old who always looks as if he has just emerged from a Happy Hour, has faced both of them of late, losing to Federer in the Australian Open final and then being brutalised by Nadal in Friday evening's Wimbledon semi-final.
"Roger is the best in the world, the most talented," says Baghdatis. "He can play everywhere, he's a great athlete. Maybe Roger is five per cent more talented than Nadal. But they're very close, they're the two best players in the world at the moment. They're playing great tennis and they are a step ahead of the other players in the top 10."
And does Rafa have any weaknesses, Marcos? "Not a lot. On defence, he is playing unbelievable. He is nowhere, then he can put the ball so deep you cannot get it back. And when he's attacking, the ball is so fast. He is serving better than before, and returning better than before. He doesn't have a lot of negative things in his game.
"Nobody expected him to go this far at Wimbledon, but he's starting to feel good on grass, starting to play great tennis. He deserves to be where he is, in the final, because he's a great player."
Nadal has always maintained that Wimbledon is the one he wants to win. Maybe he will accomplish that goal this afternoon and extend the uncanny hold he has over Federer, having won six of their seven matches, but the lad himself is modest about his chances. This, in essence, is what he says, leaving out his inclination to end every phrase with "no?"
"Sure I am surprised, but maybe I have improved a little bit. I have had some unbelievable results here. The final will be a very, very difficult match because I'll be playing someone who is one of the best in history, especially on this surface. On all surfaces, actually, but this one more than the others. So I will need to play the best match of my life to win. And I'm going to try to do that.
"I put my best into every practice, every match, every point. I am playing with a lot of concentration, with big motivation. I am playing more aggressively, for sure. I am going to the net more often, and I am running very well. I always put everything on court, so maybe that's why I am in the final."
This season Nadal is the only one to have jolted Federer out of his comfort zone. He appears to have got inside the Federer head, too, by beating him four times in 2006 (the only matches Federer has lost), most humiliatingly in the French Open final four weeks ago.
As he showed a week ago in ushering Andre Agassi off the Centre Court stage with much compassion, Nadal shows respect for his elders. His peers, too. "I respect Roger on any surface, more on grass because he is the best. He is the best on all surfaces, but here more. He is winning very easy, playing very good. So it is going to be very, very difficult, no?" Well, yes.
Switching from the punishing clay season, culminating in the most demanding tournament of all, Roland Garros, and coming on to grass and succeeding there too has been accomplished in the modern men's game only by Bjorn Borg - three times. No wonder Borg burned out at 26. Now Nadal could be the first since Borg's last of the three, achieved in 1980. Rafa is a bit cautious about his prospects on this one. "I never saw Borg, I just saw him playing some points [on TV] in the locker room the other day when it was raining, they were showing some old finals. Borg was unbelievable, no?"
This afternoon's Centre Court occasion will feature the same two finalists, the world's best two players, as the French Open, and this last happened in 1952, when Jaroslav Drobny defeated Frank Sedgman in Paris, and the Australian turned the tables on "Drob" at Wimbledon. These days, the toll is simply too great.
I remember Ivan Lendl, after one of his Roland Garros triumphs of the Eighties, turning up at Queen's the next day for the Stella Artois grass tournament, standing on the baseline and whacking the soles of his shoes with his racket head, as they do regularly at the French, to dislodge the clay. Lendl's body had made the journey to London, but the brain was still at Roland Garros.
So for Nadal to add Wimbledon to the French would have to rank as Borg-like. It may not happen this year, but Manuel Santana, interviewed elsewhere in these pages, is convinced Nadal will one day become the first Spaniard to win Wimbledon since he himself did it in 1966, while Manuel Orantes, the last Spaniard to get as far as the semi-finals, in 1972, predicts Rafa will become Spain's best-ever tennis player. Albert Costa, someone who has also won the Roland Garros crown, simply says: "Rafa is from another world, he is able to aspire to whatever he wants."
One memory lingers from Friday's semi-finals. It is of Baghdatis falling over repeatedly in the third set. It was early evening, so perhaps the grass had attracted moisture, but essentially he was being run into the ground by Nadal. Another lesson for the Federer camp to take on board.