“GO, BABY . . . That’s it, baby.” These were the cries to be heard on the outer courts of Melbourne Park last week as Donald Young Sr urged Donald Jr, his son, towards the title that further endorsed the youngster’s position as the stone-cold certainty for a fulfilling tennis future.

Young, of Atlanta, Georgia, won the Australian Open boys’ title at 15 years, six months and seven days, becoming the youngest to triumph in any of the grand-slam junior events and the youngest No 1 in the history of the ITF junior rankings, which started in 1978.

On Monday, he is scheduled to make his debut in the main draw of an ATP event, as a wild card in the SAP Open in San Jose, California. And yes, he does know the way.

There is not much of Young that immediately takes the eye. He is not particularly strong physically, he tends to idle around the back of the court and, with his white cap at its trademark jaunty angle, he resembles a comic-book urchin.

The image alters when he starts to strike a tennis ball: the flick-wrist leftie serve, the remarkable speed off the mark, the clever use of angles, the devil in the eye. When he says that his ambition is to be the No 1 in the world, it is not to be taken lightly.

Young has been cosseted by IMG, the sports management agency, since he was out of nappies and he has a lucrative endorsement deal with Nike. All he has to do is get out there and live up to his extravagant billing.

“I won my first national title when I was, like, 11, but I didn’t think I was really special. People say it, but I still see myself as normal,” he said. “I just have my Mom and Dad with me — they’ve been really all I’ve had and that’s it.”

In terms of his game, there is much to improve upon. “I like doing a lot of things on the court,” he said. “I have nothing I like doing all the time and nothing that’s overwhelmingly dominating everybody. No huge serve, no really big forehand. I would say mentally I’m strong.”

He practised in Australia with Andy Roddick, the world No 3, who is also scheduled to be in the San Jose field. “We were hitting,” Young said. “He hit a short ball. I didn’t attack it or hit it hard, I just hit it to the open court. He got upset. He wants people when they hit with him to actually jump on it and not just hit it soft.”

An interesting young man.