The England Lions thrashed the Proteas by an innings and 56 runs in Canterbury on Friday.
After resuming their second innings on 59-3, South Africa were bowled out for 183, with Aiden Markram left stranded on 88.
Sam Conners took 4-25 and Ollie Robinson 3-29.
The England Lions made a mammoth 672 in their first innings.
The Proteas gave 13 players game time in this four-day match (11 batting, 11 fielding) ahead of the first Test against England at Lord’s, which starts next Wednesday.