One must always remember that and, in truth, Rafael Nadal, winner of 14 Grand Slams, makes it difficult to forget it. One watches him take his towels in a certain order, set up his bottles precisely, shuffle his gait to avoid lines and complete a specific number of pulls at his shorts. Mercifully, he has the last down to one tug when he is receiving serves.
Sitting at changeovers, his legs shake as if one of the burly security guards had just zapped him with a Taser. When he takes to the court, he zig-zags and then jumps as if to head a cross ball. The seasoned Rafa watcher accepts all this because all genius is flawed and the world No 1 should be showed some slack.
But what happened in the first set yesterday under the roof of Centre Court was unusual even for those who have watched Rafa shake, rattle and roll all over the world. His neuroses now seem to include playing under the roof. As the rain hammered down, the 28-year-old seemed to shrink from superhero to wee boy shuddering at the thunder reverberating off the roof.
This could be written off as fevered journalistic invention were it not for the reality that Nadal has played only once under cover at Wimbledon and that was in his spectacular loss to Lukas Rosol in 2012. Nadal also admitted after his 6-7 (4) , 6-1, 6-1, 6-1 victory over Mikhail Kukushkin of Kakahstan yesterday: "I don't like to be in closed places only with lights."
This sort of championship claustrophobia is the only reasonable explanation for Nadals abject performance in the first set against an opponent who is not misrepresented by a world ranking of 63. Kukushkin, who has won one title at the age of 26, came out swinging and went for his shots with an enterprise that was admirable and predictable. The lesser player has limited chances and must seek to impose himself quickly.
Kukushkin, coached by his wife Anastasia, did just that but the surprise was how much this discomfited Nadal. He was lacklustre in the first set and feckless in the tie-break. This combination ensured that Kukushkin could sit down with barely an hour played with a one-set lead.
Whatever Nadal's frailties, they do not extend to his will or spirit and about 90 minutes later the Spaniard was celebrating a victory that reflected the gulf in class between the two players. He will now play Nick Kyrgios, the 19-year-old Australian, who defeated Jiri Vesely of the Czech Republic 3-6, 6-3, 7-5, 6-2.
Nadal believed his first-set problems were the result of fine play from his opponent. This was not the full story. Nadal was mediocre at best, but he was saved by traits that are both the result of experience and of something personal, something in the blood.
He explained his philosophy after the loss of the first set as follows: "Accept that the match is long. Accept that if he is able to play like this for three sets I will be in trouble. But always waiting that I can improve one step. If I improve one step, I can be there. I think I did."
This patience is the product of years on the Tour, facing and overcoming opponents who cause immediate but intermittent problems. He is, of course, bolstered by his extraordinary will to win.
Speaking of what has separated the Big Four of himself, Roger Federer, Novak Djokovic and Andy Murray from the rest over the years, the Spaniard said: "We were fighters for every single tournament, even if it is a Grand Slam, Masters 1000, 250, we were there fighting for the whole year, another year, another year and another year."
This has continued into June 2014. He was, though, less impressed by Federer's intervention over slow play. The Swiss has regularly criticised his rival over this and returned to the theme this week.
However, Nadal said: "People can say what they like, but they should stop trying to put pressure on the officials. The umpires should be allowed to do their jobs and umpire."
The object of his ire found the quick way to play and win yesterday. Santiago Giraldo of Colombia detained the seven-time Wimbledon winner for all of one hour 21 minutes. Federer later declared he would keep playing aggressively after winning 6-3, 6-1, 6-3. He now faces Tommy Robredo, the 32-year-old Spaniard who defeated 23-year-old Pole Jerzy Janowicz in five sets, 6-2, 6-4, 6-7 (5), 4-6, 6-3.
Federer reflected on a straightforward run into the fourth round. "It's been a good first week. I've been playing well, been feeling good, didn't drop any sets, wasn't really in danger in any of the matches," he said.
He was relaxed. Rafa was not. Strangely, that is the way both players seem to prefer it.