Ireland began the defence of their U20 Six Nations title with a 38-7 bonus-point victory over Scotland in Cardiff.
It was an even contest until early in the second half when Scotland flanker Harri Morris was red-carded for taking out Ireland full-back Jamie Osborne in the air.
This proved the decisive moment of the game and it was sailing thereafter, Richie Murphy's side running in four more tries for the concession of none.
A try from Alex Soroka and a penalty try gave Ireland a 14-7 lead at the break, Elliot Gourlay notching the Scots' score.
After the sending off, the scores flowed freely. Sam Illo, star-man Alex Kendellen, Shane Jennings and Jamie Osborne all touching down for a comprehensive win.
Elsewhere, England beat France 38-22 and Wales ran out 25-8 winners over Italy.