And they said it would never last. The first anniversary may not be marked by a party but coach and player can reflect on a season that brought an Olympic gold and silver medal and a first major title.
Murray's defeat of Roger Federer at Wimbledon amid London 2012 and his titanic victory over Novak Djokovic in the US Open final has made it a year of achievement for the 25-year-old Scot. He will head to the Australian Open next month as a viable contender to lift his second grand slam and continue to pressurise both Federer and Djokovic for the top slot in world tennis.
Mark Hodgkinson, who has watched the rise of Murray for the best part of the decade, first as tennis correspondent of the Daily Telegraph and now as founder and editor of tennisspace.com, has now written a book that serves both as a biography of the world No.3 and an assessment of his triumph at Flushing Meadows.
It is absorbing, informative and points to further intrigue and possibilities for Murray. The most pressing is just how Lendl, the 52-year-old coach, can further improve the game of his charge. The eight-time grand slam winner has already proved doubters wrong by subtly changing both the game and demeanour of the player and has, of course, watched Murray break through from a four-time losing grand slam finalist into a major winner.
"No-one ever doubted Murray's talent, just his strategy and his mental approach," says Hodgkinson. "Lendl has turned Murray, who was previously too stand-offish and passive on the big occasion, into a more attacking force. 'If you're going to lose,' Lendl has said to Murray, 'go down swinging, don't go with your ass against the back fence.'
"Since hiring Lendl, Murray hasn't spent much time with his ass against the fence. But Lendl's greatest contribution has been to improve Murray's mental approach. While Murray has not given up swearing – television broadcasters will be apologising on his behalf for a few years yet – there is a new calmness to him. And, now that he has won a grand slam, he ought to be more relaxed about his tennis and his place in the world."
Murray has been obsessive in his quest for a grand slam, devoting himself to a severe and rigorous training regime and constantly working on both technique and tactics. Hodgkinson observes in the book of the Scot: "There was no torture that he would not consider."
Does the writer believe the Dunblane player has the motivation to persevere with these efforts now the great prize has been grasped? "Murray's appetite for pain will be greater now than ever before," argues Hodgkinson. "That's not because Murray is a masochist – he isn't – but because he now knows that all those sessions on the track, in the gym and in the Bikram yoga studio are worth it, that his physical fitness helped him over the line during that five-setter against Djokovic in the US Open final. Hard work brings great reward.
"Plus, Murray's ambition was never going to be sated by just one grand slam title, and he appreciates that if he is to win a second major he must continue to improve."
The author pays proper tribute to the phenomenon of Murray, a tennis great who comes from a nation with no tradition of producing such a beast.
"I called the opening chapter, The Worst Tennis Nation On Earth. That was how Scotland was described during a Monty Python sketch about a tennis-playing blancmange," says Hodgkinson. "Dunblane is a long way from the supposed heartland of British tennis, the Home Counties, and doesn't exactly have the climate for tennis. It has been said that the most remarkable thing about Murray is his Scottishness, and there's plenty in that. How did someone from Stirlingshire ever win a grand slam singles title?
"Still, it's not as if Serbia has a long history of being a tennis superpower, and look at what Djokovic has achieved, along with the female players [Ana] Ivanovic and [Jelena] Jankovic."
Hodgkinson has watched as Murray has found it difficult to win over England in the wake of the now infamous joke with Tim Henman. His "anyone but England" crack has been met with an "anyone but Murray" faction at Wimbledon.
"Perhaps it will take Murray winning Wimbledon for Middle England to feel great affection for him," says Hodgkinson. "But there can be no doubt that the Wimbledon set have a new admiration for Murray. You could argue that Murray's tears after losing the Wimbledon final was as important a moment in gaining their admiration as his subsequent victories at the Olympics and the US Open.
"For the first time, as he wept on Centre Court, many truly cared when he lost. So when he won, and won big, with a gold medal and a first grand slam title, they had already invested something in his career, and so they cared about his victories."
Andy Murray: Champion is published by Simon and Schuster at £18.99