But it really did go down to the wire. England entered the final five minutes with a nine point lead only to concede a penalty to narrow the gap to 26-20.
With the game at stake and the loser set to possibly face New Zealand in the semi final, South Africa threw the kitchen sink at England.
Several times they looked set to cross but England wouldn't allow their line to be breached and second row Joe Launchbury deserves plaudits for two crucial tackles.
And Britton, who had come on as a replacement only moments earlier, showed nerves of steel to hit his jumper at a five metre lineout near his own line with the game at stake.
Rob Hunter's side thoroughly deserved the win for the positive way they approached the game. From the off, they took the game to the Baby Boks and Elliott Daly scored a magnificent first try.
However, they couldn't shake off South Africa and it was all square at half time at 11 all.
The second half got off to a great start as Alex Gray touched down for the second try but fly half Johan Goosen's accuracy kept South Africa in touch and kept pegging England back.
Christian Wade's superb individual try looked to guarantee England a comfortable final few minutes but, as it turned out, there were nervy moments before the celebrations could begin.