Sunshine is over-rated in sport and stillness is overestimated. In perfect weather is born the most fluent skill, but it is on imperfect days that ruggedness is revealed. In the freezing night of a 1,500m race, the sweltering cricket day of sweat and vomit, the rainy afternoon which tests the footballer's balance, we get to see character.
And so the gusting wind that led her to errors and screams and racket thumps in the US Open final was in a curious way a blessing. Because it led to survival tennis. Dig-deep tennis. C'mon-dammit-fight tennis. Serena tennis. Nature's interference just brought out the best part of her nature.
Serena's serve reminds me of Hessie Donahue, a 1892 matron who knocked out boxing champion John L. Sullivan while sparring with him. Her stroke armoury is so versatile that Victoria Azarenka said: "Sometimes she really goes for it; sometimes she finds great depth; sometimes she finds good angles."
But it is Serena's toughness, a quality easier to recognise in sport than precisely define, which is her primary trait. It is, in a sense, a defiance, which is simply, almost childishly, expressed in a match-book entry reprinted in her 2009 autobiography:
"Tell me 'No' and I'll show U I can. Tell me 'No' because I can! Tell me 'No'. Go ahead, tell me. Just tell me I can't win. Just tell me it's out of reach. Come on. I'll prove you wrong. Just tell me 'No' and watch what happens."
In another book, the gripping The Sports Gene - which I have just started - author David Epstein travels through a measured world of reflex, speed, practice, all the while splicing apart and examining the working parts of athletes. But this thing Serena has, this "irrational killer instinct" as she calls it in her book, has an unquantifiable mystery to it.
Azarenka said there's "one word" for it: champion. But Serena can't readily explain what makes champions. Can't tell you why she made her choices yesterday and won even after "not playing smart"; can't say why after twice failing to close the match she did not fade; can't explain why she looked at this pushy Belarusian, who at 24 is like a younger, fearless version of her and still believed she could win.
Athletes anyway are careful of defining their own greatness for it can smell of conceit. Roger Federer once said, "I always knew I had something special, but I didn't know it was that crazy" and his honesty did him no good. So, perhaps, it is best that Azarenka speaks for who Serena is.
"She knows what it takes to get there. I know that feeling, too. And when two people who want that feeling so bad meet, it's like a clash. That's what happens out there, those battles. And in the important moments is who is more brave, who is more consistent, or who takes more risk ... she did that today really well."
This toughness, this bravery, is stamped all over Serena's career. In 2007, ranked No.81, she won the Australian Open, one of her only two titles that year. In 2009, she won only three events: the Australian, Wimbledon and WTA Championships. In 2010, she won only two events: Australian Open and Wimbledon. Through distracted years, injured years, not-herself years, she found her toughest self at the toughest tournaments.
This toughness is evident in her longevity, even if comparisons between her energetic self (32 on Sept 26) and a flailing Federer (32 in August) are glib.
No doubt when Serena won her first Slam, in 1999, dear Rog was a No.104 racket-chucking nobody who didn't even make the main draw. But in the years since, she has played 733 matches and he 1,123, she only three sets, he sometimes five, she taking breaks, he faithful to the court, her matches taut, but his in tennis' greatest era replete with violent hitting.
It's a facile across-sex comparison and it's her durability versus her own sex, in an infinitely more physical era, that impresses. In the Open era, Chris Evert (18 singles Slams), Martina Navratilova (18) and Steffi Graf (22) won those titles across 12 years, but Serena (17) is 14 years between Slams and still winning.
But let's not be this modern tribe which starts judging, estimating and slotting athletes even before we've finished inhaling a brilliant act. Let's just acknowledge her desperate will and appreciate that unforgiving, hard tennis has its own unvarnished poetry.
Beauty, she tells us, is not just embroidery, it is also steel; it is not just intricacy, it is also resilience. Serena is not tennis' version of a painted-window, elegant church, but she is forever its solid, unyielding majestic fort.
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