Andy Murray is feeling more confident after a stellar 12 months atop the tennis world. (Paul Chiasson/AP)

There was no glaring deficiency in Andy Murray’s game — no technical glitch in his strokes, no lack of fitness, no sub-par work ethic — when he hired Hall of Famer Ivan Lendl as his coach in December 2011.

What was holding the Scot back, in his words, was feeling “a little bit like a loser” after reaching the finals of four majors without winning one.

In Lendl, Murray found a mentor with a mirror-image résumé compiled a generation earlier.

On Monday, amid his hard-court preparations for this year’s U.S. Open, Murray spoke about the difference Lendl has made, primarily in terms of his mental game, and how that translated to the glorious 12-month stretch in which he won Olympic gold; claimed that elusive first major, the 2012 U.S. Open; and lifted a nation by winning Wimbledon last month.

Any one of those qualifies as the achievement of a lifetime. The vast majority of tennis pros labor entire careers without coming close.

Yet none of these titles seems to have swelled Murray’s head or altered his no-nonsense persona. But together, they have brought about an inner change that amounts to an extra weapon on court and may well spell the difference when this year’s U.S. Open gets underway Aug. 26 with Murray as its defending champion.

“The last year for me, most importantly, it has changed my perception of myself,” said Murray, 26. “When you lose a lot of big matches even when being successful in other tournaments, and you’re still getting asked why you’re not winning the big matches, it makes you feel a bit like a loser. When I’m in those positions in the future, I should have a bit more confidence, and hopefully that’ll help me.”

Murray was in an enviable position when he sought out Lendl, a former No. 1 who won eight major titles in a 16-year career. Murray was No. 4 in the world in arguably the most competitive era in the history of men’s tennis, during the prime of Roger Federer and Rafael Nadal and emergence of Novak Djokovic. While he possessed the requisite skills of a champion, he felt he hadn’t reached his potential and went through a flurry of coaches trying.

In Lendl, he found a soulmate — a player who had lost four finals to the greats of his era, such as Bjorn Borg and Jimmy Connors, before winning his first.

“The thing I most benefitted from is being able to speak to someone who had been in the position I was in, in terms of losing the first few Grand Slam finals,” Murray said. “Having been around the top of the game for quite a few years but not necessarily feeling like you’d achieved much, I hadn’t reached my potential.”

Loath to rank one achievement of these last 12 months over another, Murray ascribes a superlative to each.

The Olympic gold medal: “In terms of actual experience, I really enjoyed the Olympics probably the most. I loved the whole two weeks, got to watch a load of other sports, and compete in an Olympics on my home soil.”

The 2012 U.S. Open: “Massive, massive relief to have finally done that.”

His Wimbledon victory, the first by a British man in 77 years: “The sweetest, because of the amount of pressure I was under, and the way the final ended the year before [in tears, following a four-set loss to Federer]. That would be the sweetest.”

It’s only recently that Murray has fully grasped that he won Wimbledon. The immediate aftermath, he says, was “quite surreal.”

“Literally every time I turned the television on I was there,” he said. “It felt like a movie. It didn’t feel real.”