Japan players and fans shed tears of joy at the end of a thrilling encounter that ebbed and flowed, but victory was fully deserved after a tenacious performance by the underdogs at the Brighton Community Stadium on Sunday morning.
South Africa had sounded a note of caution ahead of the game, but few, if any, would have predicted defeat at the hands of an opponent that had previously won only once in 24 World Cup outings.
The Boks outscored Japan four tries to three, but the kicking of full-back Ayumu Goromaru, who also scored a try for a personal 24-point tally, kept Japan in the contest to set up a remarkable last eight minutes of pressure under which the Boks finally buckled.
"We've worked for this for the last four years," victorious captain Michael Leitch said immediately after the game.
Ferocious tackling from Japan kept them within two points of the Springboks at half-time after driving mauls brought tries for South Africa's Francois Louw and Bismarck du Plessis, with Leitch touching down for Japan.
The reliable boot of Goromaru nudged Japan in front early in the second half, but that was quickly cancelled out by a try from South African lock Lood De Jager.
Both sides exchanged a series of penalties before Springboks snatched another try when replacement Adriaan Strauss burst through the defence. But then Japan found space out wide, sending Goromaru in at the corner; his conversion levelling the scores.
Another Springbok penalty looked like breaking Japanese hearts, only for Hesketh to grab his place in rugby history in the final play of the game.