BOSTON, Massachusetts - A New Zealand kid has shocked the athletics world with a stunning sub-4 minute mile run, and he says he has more 'in the tank.'

The teenager was competing in the John Thomas Terrier Classic in Boston, Massachusetts on Saturday, against a field of professional athletes.

The 16-year-old stunned officials and the crowd when he ran the mile in an astonishing 3:48.88 minutes, the fastest ever mile run by a junior athlete (under 18), and a new national record for New Zealand..

"I didn't feel like I was going that fast to be honest. I still don't believe it… I'm completely stoked," young Sam Ruthe told the crowd when interviewed by the track broadcaster after the race,

Ruthe had worked himself into fourth place early, before working his way into third, and then second with two laps left. He let himself go with a burst of lightning speed in the last 100 metres, finishing 1.43 seconds in front of  Belgian Pieter Sisk who finished in second place.

The run was more remarkable considering the youngster had spent around 20 hours in the air, in a series of flights over a period of fifty hours, including stopovers, flying to Boston from New Zealand, on Tuesday/Wednesday,

New Zealand runners have a long history of producing world class middle distance runners, none more famous than Sir John Walker, who was the first person to run a sub-3:50 minute mile, and that was in 1982, more than a quarter century before Ruthe was even born. Walker was aged 30, nearly double Sam Ruthe's age, a sure indicator of what lies ahead

"I really didn't expect to get Walker's national record," Ruthe told CNN Sports Saturday. "I hoped to get it one day but that was a real surprise as I thought it may have been three or four years away. I feel like I'm the luckiest person in the world."

New Zealand officials may now have to consider adding the teenager to the team to compete in the Commonwealth Games in Glasgow this year.