Can explaining how the tennis player Novak Djokovic wins so many matches lead us to live better lives as employees, parents, spouses and friends? It might sound crazy but I think it can.

Djokovic at his best is absolutely brilliant. That’s not the point. The astonishing thing is that when Djokovic is below par, when his game is out of kilter, he is still very good indeed. That is where he steals a margin on his competitors. His best form rivals anyone’s best. But his worst is definitely better than anybody else’s worst. Djokovic’s baseline (the tennis overtones are coincidental) is the highest in tennis and perhaps anywhere in world sport.

We tend to think of brilliance in terms of peaks of inspiration, what athletes refer to as “the zone”. This calm yet euphoric state is the focus of most sports psychology and the nirvana promised by the lucrative sport-business lecture circuit. At least as important, however, is how good you are when you are completely out of the zone. Many top players are unstoppable when they are on form; only a tiny number are still hard to beat when they are bumping along the baseline of their performance range.

Djokovic’s victory over Andy Murray in the final of the Australian Open last month was a classic case study. Murray played superbly for two sets of enthralling tennis. Had it been a boxing match, he would have clinched both rounds. During this phase of the match Murray was more exuberantly confident than I’ve ever seen him – punching the air, extravagantly nodding his head, calling out to his coaches: “I’ve got this!” Where Murray’s blood was up, Djokovic looked out of sorts, oddly muted. The champion was there for the taking, ready to be toppled. Then there was the annoying small detail: the score. This read: one set all, both decided by tie-break. Djokovic was clearly losing, we could all see that – everyone, that is, except the scoreboard.

Consider Andy Murray’s experience of getting to that stage. He knew, in a match likely to swing several times in momentum, that this early stage was his period of ascendancy. In normal circumstances, a player does not exert as much energy when he is on top – because he is dominating the rallies, it is his opponent who does most of the running around. But against Djokovic, it rarely works out that way. He is so resilient in his bad spells, so hard to break down, that the process is almost equally exhausting for both players. Then, when Djokovic does click back into gear, he finds himself playing against a diminished opponent, both physically and mentally.

The question of whether Djokovic unsettled Murray by faking an injury has been overstated. Where Djokovic certainly did unsettle Murray was by taking him to the brink of exhaustion, even when it felt like Murray was winning. Beating Djokovic is like climbing the north face of the Eiger: there are no easy footholds on the sheer ice. Djokovic’s high baseline suffocates his opponents by making them play at an uncomfortably high altitude for hours, until – oxygen-deprived and disorientated – they crash back down to earth.

We often explain consistency in psychological terms. But temperament and technique are inseparable. When I jotted down a list of sportsmen with exceptionally high baselines – the Italian footballer Paolo Maldini, the South African cricketer Jacques Kallis, the New Zealand rugby player Richie McCaw and the Spanish footballer Xavi Hernandez – they all had superb technique in common. Djokovic, too, has the best all-round technique in tennis. The most under­rated benefit of great technique is that it reduces the burden of anxiety. A player with great technique might lose but he is less likely to collapse.

“Technique is for an off-day,” the conductor Christopher Seaman told me recently. After all, when you’re in the zone, technique disappears and pure instinct takes over. Inside Conducting, Seaman’s superb book on his craft, is an expansion of that theme – how to balance the deliberate and the instinctive.

I remember talking in the late 1990s to Matthew Parris, then in full flow as the Times’s daily parliamentary sketchwriter. “What’s the hallmark of a great journalist?” I wondered. One aspect of his reply, flinty and unsentimental, surprised me: “Editors want to know that when you’re having a bad day, you’ll still be competent.” But Parris was right: there are many more journalists capable of being very good on their good days than there are columns to go around.

Howard Marks, the legendary American investor, has explored a similar point about exposure to financial risk. It’s not just how good you are in the good times, it is how moderate you are in the bad times. Nor does the conventional concept of averages capture the risks of a sudden decline in performance. “Never forget the six-foot-tall man,” Marks points out, “who drowned crossing the stream that was five feet on average.”

What can we, in civilian life, learn from the implications of a high baseline? Most of life is co-operative rather than competitive. Our bad days lead not to our own defeat but to the subtle diminution of the rooms we occupy. At our worst, we dampen the family mood at breakfast, reduce the optimism of the workplace and undermine the warmth of the evening.

But by how much? That is an undervalued criterion in gauging a good life. Every­one suffers fluctuations in mood; some people hide it better than others and, in the process, imperceptibly though significantly improve the lives of everyone around them.

I wonder if the eulogy “At his best, he was very good” should be replaced by “At his worst, he was better than most”.

Ed Smith’s latest book is “Luck: a Fresh Look at Fortune” (Bloomsbury)