He had a nightmare in a dream match and in seven dreadful minutes presented Sheffield Wednesday with three goals. The score zoomed from 1-1 to 4-1 against United as Briggs let a shot from Alan Finney spin out of his arms (30 minutes), grasped with wild inaccuracy at a header from Keith Ellis (33 minutes) and, after diving bravely at the toes of Ellis, failed to grab the ball (37 minutes).
And there were no smiles in the Irish eyes of Briggs when the whistle mercifully ended the slaughter at 7-2, United's worst post-war home defeat.
The boy, in white pants six inches too short for his lanky legs, came off the field last and alone - clutching his cap, covering his tears with his left hand and loping with schoolboy awkwardness towards the players' tunnel.
In his last stride he paused to look up shyly at the packed stand, expecting, perhaps, assault or abuse. He received neither. Manchester, bless its broken, sporting heart, gave him a cheer.
So now Sheffield go to Leyton Orient in the fifth round for London's only Cup tie. Orient manager Les Gore watched this replay and must have been impressed by an all-round side that can play rough or smooth.
They needed their toughness against some of the tackles of United captain Maurice Setters and inside-right Nobby Stiles. But these were jarring notes in the subtle, inventive rhythm of United's attack. I am sure they would have won but for this difference - United were shooting against Ron Springett of England, Wednesday only against shattered Briggs of the `A' team.
Goals: Fantham (3) 0-1; Pearson (4) 1-1; Finney (30) 1-2; Ellis (33) 1-3; Ellis (37) 1-4; Fantham (52) 1-5; Dawson 2-5 (65); Ellis (74) 2- 6; Finney (84) 2-7.
Manchester United: Briggs; Brennan, Cantwell; Setters, Foulkes, Nicholson; Quixall, Stiles, Dawson, Pearson, Charlton.
Sheffield Wednesday: Springett; Johnson, Megson; McAnearney, O'Donnell, Kay; Wilkinson, Craig, Ellis, Fantham, Finney.
Wednesday were eventually knocked out by Burnley in the quarter-finals but went on to claim the runners-up spot behind Tottenham in the First Division championship. Briggs played only 11 games for United (who finished a distant seventh in the League that season) and three years later moved to Swansea City. He also played for Bristol Rovers and won two caps for Northern Ireland.