Underarm delivery "greatest thing to happen to NZ cricket" says Greg Chappell

The infamous underarm delivery was the "greatest thing to happen to New Zealand cricket" according to its mastermind Greg Chappell.

A documentary set to be released in New Zealand next week will inspect every aspect of one of the most defining incidents in the trans-Tasman sporting rivalry.

Australia's Trevor Chappell's underarm bowl to New Zealand's Brian McKechnie at the Melbourne Cricket Ground happened 38 years ago this Friday.

The documentary, produced by ACC commentator Lee Baker, interviewed key members of each team, was a cathartic experience for both Chappell brothers says interviewer Eric Young.

"Some of the things Greg has to say about his little brother will touch anyone who has a little brother," Young told AAP.

"There are some quite moving moments.

"Greg's very honest about his emotional wellbeing on that day. His mental and physical exhaustion, is the origin story of underarm."

It was Greg who instructed his brother Trevor to execute the rollout to deny McKechnie a chance for a match-tying six, which led the Kiwi tailender to fling his bat in disgust after blocking the ball.

For New Zealanders, the underarm led to 38 years of positive effects and the moral high ground over Australia, with captain at the time Geoff Howarth crediting the incident to an explosion in interest in the Black Caps.

"Geoff said it was the greatest thing to happen to New Zealand cricket," said Young.

"We call it the ball that changed cricket."

Underarm: The Ball That Changed Cricket will air on February 4 at 7.30pm on Prime.

This article was first published on nzherald.co.nz and is republished here with permission.