When first-choice props Ray McLoughlin and Sandy Carmichael were invalided out of the 1971 Lions tour amidst the mayhem of the game against Canterbury , New Zealanders believed the visitors' pack had been delivered a fatal blow.
Instead, understudies Ian McLauchlan and Sean Lynch stepped into the breach and built the platform on which the Lions backs were able to earn the team's first series victory over the All Blacks.
The locals had been particularly sceptical of McLauchlan's worth, considering him far too small at 5'8 ½ " to dominate his opponents in the set-piece.
They could not have been more wrong.
By the end of the tour, it wasn't just McLauchlan's team-mates who called him 'Mighty Mouse'. And by the time he had helped dismantle traditionally the fiercest of all scrummages in South Africa three years later, he was recognised unquestionably as the model loosehead prop of his age.
Throughout the 1971 campaign, the Jordanhill and Scotland forward exposed countless taller props with a strength and technique that were only intensified by the awkwardness of the angles with which he applied them.
McLauchlan's comparative lack of bulk also added to his contribution in the loose, exemplified by the decisive try he scored against New Zealand in the first Test of 1971.
On the Lions' first excursion into All Black territory, the Scot harassed full-back Fergie McCormick into an error and in the ensuing panic charged down Alan Sutherland's attempted clearance to score.
By the time of the 1974 Lions tour, McLauchlan was captain of Scotland , going on to lead his country 19 times and to 10 victories, both of which were records.
In South Africa , he was an established cornerstone of the Lions pack and formed arguably its greatest front row, alongside hooker Bobby Windsor and tighthead Fran Cotton.
McLauchlan made 13 appearances on tour and received the ultimate recognition of his contribution to the side in the sixth of those matches, when he captained the Lions against Southern Universities.