Heriots opened in strong fashion taking an early lead with Munster conceding two tries in the first 12 minutes of play. The Munster young guns were not deterred and responded well after 20 minutes with a Michael Kelleher try which Cormac O'Flynn failed to convert.
The match was highly competitive and very physical with Heriots fielding a huge pack and opting for the scrum with every penalty opportunity. But Munster continued to attack and a well worked move down the wing resulted in Dan Heffernan squeezing over the line, bringing the score to 12-10 in favour of Heriots at the break.
Munster rang in the changes at halftime making a host of substitutions and before the new players had time to settle Heriots broke the Munster defence once again pushing ahead 17-10.
On the back-foot again Munster pressed on and mounted a fight back with their hard work and patience resulting in a converted try scored by winger Craig O'Hanlon.
It was all square going into the final quarter and Heriots applied considerable pressure in an effort to secure the home victory, but the Munster defence never wavered and held firm.
With five minutes left on the clock Munster were awarded a penalty and Gareth Quinn McDonagh showed great poise when he slotted the penalty from left of the posts to secure a well earned victory for the Munster youngsters, 20-17.
The Munster U20s completed their weekend with a further training session on Sunday morning, and next up they will take on a Munster Academy select XV this Friday the 28th in Fermoy RFC, ko 2pm.
Munster U20s Squad: Ger Burke; Gareth Quinn McDonagh; Duncan Casey; Brian Cagney; Brendan Cullinane; JP Cooney; Brian Hayes; Edward Kelly; Sean Duggan; Dave O'Callaghan; John Quill; Dean Landy; Patrick Butler; Dan Heffernan; David O'Driscoll; Brian Slater; Michael Kelliher; Cormac O'Flynn; Kevin Kidney; Joe Holland; Simon Zebo; Craig O'Hanlon; Gavin Nugent; Lukas Kunz; Darren Moroney; Luke O'Dea; Johnny McCarthy.
Munster U20s Management Team:
Anthony Foley - Head Coach
Ian Costello - Assistant / Backs Coach
Alan Miller - Manager
Feargal O'Callaghan - Fitness & Conditioning Coach
Paudie Roche - Assistant Fitness & Conditioning Coach
Damien Mordan - Physio
Alan Hickey - Kit Manager
Elliot Corcoran - Video Analyst
Munster U20s Interprovincial Fixtures:
Connacht - Away - Showgrounds - Friday 11/09/09
Leinster - Home - Thomond Park - Friday 18/09/09
Ulster - Away - Ravenhill - Friday 25/09/09