Agassi was in New Zealand for some heli-skiing.
James was told the night before but had to keep it quiet because celebrities prefer anonymity when visiting the resort.
"I was fizzing the whole day," James said.
"Agassi was my hero and had a big influence on my game. I admired his aggression."
Agassi was noted for his powerful serve and this has become a significant part of James' game and he now serves at a speed of 180kmh.
James started playing tennis at the age of 8 and followed in the footsteps of Queenstown-based Riki and Ben McLachlan, who are now on tennis scholarships at United States universities.
That is James' immediate goal and he expects to start a four-year contract at university in a year's time.
The biggest influence on his tennis is his Queenstown coach Lan Bale, who has coached at Berkeley, in California.
James has represented New Zealand junior teams in China and Australia and, through the influence of his coach, has played in major tournaments in the United States.
"Having Lan as my coach and mentor has opened up a world of possibilities that would have been impossible to achieve," he said.
The overseas experience James has gained over the last four years has given him a good insight into what is required to reach professional ranks in the sport.
"I have learnt how to prepare for tournaments, how to compete and how to handle the pressure," he said.
"I now realise how important it is to make the most of any opportunities and stand on my own feet."
His overseas ventures have given James an understanding of how the rest of the world lives.
A tournament in the Shenzhen province of China made him aware of the poverty in other parts of the world.
"It's a completely different culture," he said.
"We are very lucky to live in New Zealand."
When James has completed his university studies in the United States, he hopes to join the world professional tour
Fast Lane
Name: Harry James (18).
School: John McGlashan College.
Sport: Tennis.
Achievements: Top Otago male junior; represented NZ in the United States, China and Australia; world junior ranking 2033rd.
Agassi was in New Zealand for some heli-skiing.
James was told the night before but had to keep it quiet because celebrities prefer anonymity when visiting the resort.
"I was fizzing the whole day," James said.
"Agassi was my hero and had a big influence on my game. I admired his aggression."
Agassi was noted for his powerful serve and this has become a significant part of James' game and he now serves at a speed of 180kmh.
James started playing tennis at the age of 8 and followed in the footsteps of Queenstown-based Riki and Ben McLachlan, who are now on tennis scholarships at United States universities.
That is James' immediate goal and he expects to start a four-year contract at university in a year's time.
The biggest influence on his tennis is his Queenstown coach Lan Bale, who has coached at Berkeley, in California.
James has represented New Zealand junior teams in China and Australia and, through the influence of his coach, has played in major tournaments in the United States.
"Having Lan as my coach and mentor has opened up a world of possibilities that would have been impossible to achieve," he said.
The overseas experience James has gained over the last four years has given him a good insight into what is required to reach professional ranks in the sport.
"I have learnt how to prepare for tournaments, how to compete and how to handle the pressure," he said.
"I now realise how important it is to make the most of any opportunities and stand on my own feet."
His overseas ventures have given James an understanding of how the rest of the world lives.
A tournament in the Shenzhen province of China made him aware of the poverty in other parts of the world.
"It's a completely different culture," he said.
"We are very lucky to live in New Zealand."
When James has completed his university studies in the United States, he hopes to join the world professional tour
Fast Lane
Name: Harry James (18).
School: John McGlashan College.
Sport: Tennis.
Achievements: Top Otago male junior; represented NZ in the United States, China and Australia; world junior ranking 2033rd.