Having taken a first-innings lead of 264, England bowled out South Africa for 179 on Saturday to earn their fifth win in six tests and bounce back from the disappointment of losing the series opener at Lord's.
Stokes scored 103 in England's first innings and wicketkeeper Ben Foakes smashed an unbeaten 113, while veteran bowler James Anderson became the leading wicket-taker among pace bowlers across all formats.
"Cricket is about how you bat, bowl and field and I think that the way we batted, bowled and fielded this whole game is like the benchmark of the standards of what we set," said Stokes.
"I think what we did incredibly well with the bat was assess that we didn't feel this was a wicket where we could go out and play in the way that we spoke about.
"I think that is real progress for the side."
The teams will now meet in the series decider at The Oval from September 8.
