Scotland 19 Ireland 20
Ireland dished out a double of heartbreak to Scotland when the Under-20 side came with a match-winning try seven minutes from time to get their campaign off to a winning start at Cumbernauld.
But then the Scots blew a chance to win it two minutes from time when they missed a penalty and Ireland held on for what is only their second ever win in Scotland in the Six Nations.
Flanker Paul Boyle was the late try-scoring hero for Ireland as they completed the double over Scotland, having earlier won the women's encounter with a late try.
Ireland were chasing the game from the outset as Scotland, with eight survivors from last season, got an early grip at Broadwood Stadium.
The Scots, with an impressive pack, hit the front after eight minutes when a penalty to the left corner yielded the opening try.
Ireland did well to defend three close-range drives but when scrumhalf Andrew Simmers popped it out, centre Cameron Hutchison timed his run to perfection to crash over.
Henderson added the extras to make it 7-0 but Ireland, with tighthead Peter Cooper, lock Fineen Wycherley and flanker Cillian Gallagher, a survivor from last year, making an impact, Nigel Carolan's men got back in the game.
Johnny McPhillips, the only other member of last year’s squad which reached the U20 World Championship final, slotted a couple of penalties to make it 7-6 at the end of the opening quarter.
However, Scotland picked it up again with fleet-footed fullback Darcy Graham superb, they dominated most of the remainder of the opening half and while St Mary's Jordan Larmour denied Graham a try in the corner eight minutes from the break, two more penalties from Henderson made it 13-6 at the interval.
Ireland hit back after the restart and were rewarded by going to the corner with a penalty just four minutes in. Lock Oisin Dowling collected the throw, Ireland got the drive on and hooker Tadgh McEvoy peeled around to score. The conversion from McPhillips tied the match at 13-13.
But two more penalties from Henderson saw Scotland take a 19-13 lead into the final quarter with the wind at their backs.
But then seven minutes from time Ireland got in for a superb forwards’ try, mauling their way from 35 metres out on the right through about a dozen phases before flanker Boyle managed to get over.
McPhillips added the points to edge Ireland 20-19 in front going into the closing stages.
Then Scotland had a chance to win it but Henderson missed the target from 42 metres after Irish hooker McElroy was pinged for not rolling away.
SCOTLAND: D Graham; R Nairn, C Pringle, C Hutchison, R McCann; J Henderson, A Simmers; G Thornton, F Renwick, A Nicol; A Craig, C Hunter-Hill; L Crosbie, M Fagerson, T Dodd.
Replacements: C Shiel for Simmers (13-18 mins), F Bradbury for Thornton (40 mins), H Bain for Craig (55 mins), B Flockhart for Dodd (55 mins), D Winning for Nicol (74 mins), S McDowall for Hutchison (75 mins).
IRELAND: J Kelly; J Larmour, G Mullin, C Frawley, C Hogan; J McPhillips, J Stewart; J Conway, T McElroy, P Cooper; F Wycherley, O Dowling; C Gallagher, P Boyle, C Doris.
Replacements: T O'Brien for Kelly (63 mins), C Connolly Cooper for (63 mins), J Lyons for Stewart (67 mins), M Rea for Doris (75 mins), R Mulvihill for Conway (75 mins), A Moloney for McElroy (78 mins).
Referee: Christophe Ridley (England)