NEW YORK: A grim-faced Ivan Lendl watched Andy Murray throughout the US Open, but even his stoic countenance wavered just a bit as he watched his pupil celebrate a long-awaited first Grand Slam title on Monday.

Murray captured the US Open crown with a 7-6 (12/10), 7-5, 2-6, 3-6, 6-2 victory over Serbian defending champion Novak Djokovic, becoming the first British man since Englishman Fred Perry in 1936 to win a Grand Slam title.

The 25-year-old Scotsman lost his first four career Grand Slam finals, an Open-era futility run matched only by Lendl, who went on to win eight Grand Slam titles in his career, the last of them at the 1990 Australian Open.

The 52-year-old Czech began working with Murray nine months ago and the partnership paid dividends when Murray reached the Wimbledon final and captured Olympic gold in the past two months.

When Murray celebrated his Grand Slam breakthrough, Lendl's stony visage wavered ever-so slightly as he stood inside Arthur Ashe Stadium. Were those nigh-invisible curls at the edge of his lips a smile?

“That's almost a smile for him,” Murray said as the crowd roared in delight.

Afterward, Murray was asked about maintaining his typical mellow demeanor in the wake of the triumph of a lifetime.

“I think we're sort of learning from Lendl a little bit,” Murray said.

“He doesn't smile a whole lot.”

What he has done is help guide Murray to the promised land, pushing the maturing tennis star's mental game to new heights.

After all, Lendl was the only other man on the planet who had gone 0-4 in his first Grand Slam finals and he had recovered to win eight Grand Slams.

“I think he definitely helped, that's for sure,” Murray said.

“It's hard to say in terms of a percentage how much difference he will have made.

“But I have enjoyed working with him. I have listened to him a lot. He has definitely helped. Having him in your corner for any player would be a big bonus. Not many guys have won as much as he did want to go into coaching or want to be around tennis.”

Murray feels like he has brought a new dimension for Lendl as well, having given the former John McEnroe nemesis a new lease on tennis life.

“Because he had such a long break after he finished, he wanted to get back into it,” Murray said.

“I think he's enjoying it. I'm sure it gave a little boost to his ego that I won after just sort of nine months with him.

“It has been great so far and I hope we can keep working well together.”

World No. 2 Djokovic can see the difference Lendl has helped make. “It's mental in the end mostly,” Djokovic said.

“He has maybe couple of adjustments in his game. Maybe he goes for forehand more than he used to. But I think it was mental for him in the end to really make a breakthrough.

“He definitely changed his mindset towards the big matches. A lot of expectations. He has won it in a very impressive way.”