McGarry (44), the head of physical education at Otago Boys High School, played 87 games and is the highest-capped New Zealand-born All White.
"It would be the start of better and bigger things to come," McGarry told the Otago Daily Times yesterday.
"But even if we don't win, it's not the end of the world. We have quality players in our under-age teams and several players in our under-17 men's team have been signed by English professional clubs."
It was a huge boost to New Zealand football for the under-17 men's and women's teams to play in world championships, he said.
"We are growing a huge base and this is the best opportunity we have had for 27 years to reach the World Cup finals, in South Africa."
It is a busy time at work for McGarry and he is not able to travel to Wellington for the game tomorrow.
"But I will be glued to the television to watch the game," he said.
"I am anticipating a win.
"I'm hoping for a cold day in Wellington to give us every chance of winning."
McGarry said it was important for the All Whites to start well and not concede an early goal.
"If they score early, we will have to score two goals to catch up. The 0-0 draw in Bahrain was not the best result for us. That is why we need to start the game well."
McGarry comes from a football-mad family and was a 17-year-old pupil at The Taieri High School in 1982 when New Zealand last qualified for the World Cup.
"The road to Spain was exciting and the country got behind the team," McGarry said.
"We had Steve Wooddin from Otago in the team."
Wooddin played for the All Whites from 1986-97 but but did not achieve his dream of playing in a World Cup.
"I played in three qualifying tournaments. We got close but never quite made it. . . . There are a lot of very good nations and world-class players who miss out."
Israel and Australia blocked New Zealand' s progress to the World Cup finals in McGarry's time.
"It is always pretty tough to get there," he said.
"We have a better opportunity now because Australia has gone into the Asian group."