From a routine patrol crossing a muddy ditch in Afghanistan, where a land mine blast changed his life in a split-second, to the hothouse of the US Open, American soldier Ryan McIntosh has come a long way.

Two years ago, McIntosh, just 21, lost part of his right leg when he stepped on a mine planted by the Taliban.

The explosion launched him three metres into the air, the bloody shock of the attack knocking him unconscious with surgeons having no choice but to amputate his right leg below the knee.

But with a wife and a son to support, and another child on the way, McIntosh has refused to surrender to his disability and when he tried out with 600 other hopefuls to become a ballboy at the US Open, he already had a unique advantage.

“They asked me if I could throw a tennis ball. I said, ‘Hey if I can throw a hand grenade, I can throw a tennis ball.’ Grenades are a lot heavier,” said the 23-year-old.

McIntosh is still in the army, working as a sports coach with other disabled servicemen and women at Fort Sam Houston in Texas.

On Monday, at the US Open, he was centre-stage on the showpiece Arthur Ashe Stadium during American star Serena Williams’s fourth-round match.

It was an emotional moment for McIntosh as the occasion coincided with the tournament’s Military Appreciation Day where he, as well as other US Army, Navy and Air Force personnel, were given a standing ovation by the 20,000 crowd.

McIntosh, who relies on a carbon fibre blade prosthetic while on court, doesn’t over-dramatise the horror of his tour of duty, preferring to emphasise that he wants to be an inspiration to other wounded servicemen and his son.

“Knowing I had a son, I wanted to be at his side, coach him, give him a push,” said McIntosh.

“I also want other wounded soldiers to know that even though what happened can be an obstacle, at the same time the human will is very powerful and you can overcome those obstacles.”