Andy Murray puts faith in Ivan Lendl
Other than deciding where to serve and how to play his first championship point in a Grand Slam final, when that occurs, as I still believe it will do, the hiring of Ivan Lendl as a full-time coach may prove to be the most important decision Andy Murray ever makes.
Lendl, despite no previous experience of coaching on the tour, brings enormous credibility and huge experience of playing at the very top level. He won eight major titles and spent much of the 1980s as world number one.
I'm sure he won't attempt to alter Murray's natural style of play or drastically remodel certain strokes, and of course there is no guarantee his arrival will make any difference whatsoever, but one piece of advice, perhaps a small slice of fresh perspective from an outsider with major-winning credentials, could make all the difference as the quest for a first grand Slam title continues.
Murray will certainly hope so. They team up this week in Australia with the 24-year old, having enjoyed a terrific off-season of physical training in Miami, due to play at the Brisbane International.
Lendl won 94 ATP Tour titles in a career that spanned 16 years. Photo - Getty
Getting a coach in place right at the start of the year is a great move. The Australian Open begins in a fortnight and Murray will still be looking to impress his new coach during the Melbourne fortnight.
For 18 months he has travelled the world with a team of good guys; a coach, a physio, two fitness trainers, a nutritionist. As well as being excellent at their jobs, they have all become good friends and touring companions.
But there has been no definite leader of the group and this is the big change.
Lendl comes in from the periphery. A safe existence from his home in Florida with his golf-playing daughters and his thriving tennis academy.
I very much doubt he has taken this job to win mates, play computer games and hang out with a bunch of 20-somethings. He will get on famously with the team because they are a great bunch, but he has accepted this challenge because he believes he can help Andy Murray win multiple major championships.
He will stand as that figure of respect, a fresh voice, and a leader of the team.
He will not stand for being abused as he sits in the stands. Last year Murray lost his rag at key moments of key matches - ranting and raving at his support team - so if Lendl's presence wipes that out, he will have instant progress. I suspect that can already be taken as read.
Because he firmly believes in his own way of doing things - always has - this is a very brave decision by Murray.
It's effectively an admission that he cannot meet the extraordinary challenge of winning a major all by himself. He has abdicated some of his own power.
He is more than capable of winning a major without a coach - he has reached three finals after all, and in weaker eras would probably have won a couple of majors by now - but regardless of whether the Lendl thing works out, this invitation to someone from the outside is a huge stride forward. There are many others who would dearly love to help him.
Murray turns 25 this year and knows his window of major-winning opportunity is gradually closing year on year. As he strives to maximise his potential, surely any sportsman's key objective, having an eight-time Grand Slam champion in his corner can only help.
After losing his first four major finals, Lendl won eight and became world number one. Murray, who has lost his first three, now needs to learn how the Czech recovered from those early setbacks to achieve a glittering career. And then try to do the same.
Hard, incredibly hard, but not impossible.