Novak Djokovic is a lean whippet of a man, Boris Becker was a pit bull. Djokovic once put on a wig for fun and danced in public; Becker rumouredly wore wigs in public so no one could recognise him. Djokovic needs to win the French Open to complete his Grand Slam set; Becker has won 49 titles, none of them on clay.
Welcome to December and the strange tennis marriage. Fortunately, Serb and German are not without similarity: Both are given to theatrical mutterings on court.
This union of legends appears all rather romantic, but intrinsically coaching is a practical exercise which involves the ruthless player constantly asking: What's good for me? And so one day he embraces his coach in public as family, the next day - or after 15 years in David Ferrer's case with Javier Piles - he culls him as inept employee.
It appears harsh yet this is the pull of perfection: Athletes want answers and no one has them all. In time, even the most inspirational tutor can turn into a boring nag. Hell, even Yoda with his backward English - "stopped they must be; on this all depends" - would be kicked out the door.
But Djokovic-Becker is new and we search hard for clues to understand this alliance. Coaching fascinates for it is a throwback to the ancient idea of gurus - except in sport the pupil puts teacher on contract - and deep meaning is looked for in every merging. Surely winning is a science that only few can impart, such as men of high tennis IQ like Mats Wilander.
Not quite. As coach, Wilander won little, while mothers (Melanie Molitor, Martina Hingis' mum) and fathers (Jennifer Capriati's dad, Stefano), some with no grand pedigree in tennis, have coached successfully. Let's not forget uncles called Toni and snoring husbands named Jiang Shan (who coached Li Na).
Coaching is not particle physics clearly. It is also slightly sexist. Most women are coached by men and very few men by women. Neither makes sense. The combative Martina Navratilova could coach anyone, so might the tactical Chris Evert, certainly the adroit Hingis. Reading tennis or unravelling technique are not exclusively male virtues. After all, two women named Gloria and Bertha built a savage male warrior called Jimmy Connors.
Coaching is also a modern fashion for we are circled by life coaches, personal coaches, business coaches and even dating coaches, like the one from the film Hitch who utters nauseous lines like: "Life is not the amount of breaths you take, it's the moments that take your breath away."
Yet, even if modern entourages seem indulgent, the underlying idea makes sense: To improve we need our skills to be scrutinised. In his superb piece on the subject in the New Yorker, Atul Gawande quotes a soprano who refers to coaches as "outside ears" and says: "The voice is so mysterious and fragile... What we hear as we are singing is not what the audience hears."
Tennis players, too, need new eyes and different voices. Some need tactical help, some confidence management, some a finer versatility. Some require constant reinforcement, some an occasional nudge. But all crave advantage.
Djokovic's game, when humming, appears devoid of glitches, yet he is an incomplete force - else he wouldn't have lost at the 2013 French and US Opens to Rafael Nadal. Becker's hiring is in effect an act of humility for the Serb is admitting he needs to get better.
Becker retains his sense of intrigue. For an agile player, he is a plodder in commentary, yet this hardly points to failed communication skills. He may not express tennis interestingly to us amateurs, but may be more gifted in the language that champions speak.
Becker emitted intensity and radiated intimidation and Bob Brett, his coach from 1987-91, told me: "Boris' strengths were attack and putting pressure and perhaps he could help Novak in those areas."
But how do you refashion an instinct? You can teach an approach shot, a volley, a heftier serve, you can instruct the athlete to think "attack", but can he do it at 30-40 down at 4-5? Or will Djokovic return to his comfort zone which is to neutralise a rival?
Instincts take long and hard months to recraft and short coaching flirtations won't suffice. Yet this is what makes this union enticing and Becker will not flinch. Of the gifts he could give the already hardy Djokovic, playing through pressure could be one.
The German survived the insanity of his teen success, when he reportedly said of his worshippers: "When I looked at the eyes of my fans, I thought I was looking at monsters." It is through this unrelenting psychological landscape that he might be a fair guide to Djokovic. If not, then boom, he will be gone.
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