Captain Michael Vaughan insists there is more to come from England after they won their eighth successive Test.
After beating South Africa, Vaughan looked ahead to the next Test, saying: "We didn't play to our full potential - we probably played to about 80%.
"There were periods when we should have dominated the South Africans more, especially in our first innings.
"That didn't happen and hopefully in Durban if it happens again we will put up more of a lead."
Andrew Strauss was named man of the match after hitting a first-innings century and an unbeaten 94.
And Simon Jones' four-wicket haul on Monday helped cut the hosts down from 201-4 to 229 all out, leaving England needing just 142 more for victory.
Vaughan said: "Andrew Strauss was outstanding and Simon Jones changed the game for us.
"There was a period of play where the South Africans started to get on top and Simon Jones made the difference."
In a rare display of emotion, coach Duncan Fletcher expressed his pride after the victory.
"You can't go out looking to make history, it just comes along. The guys have done very well," he said.
"It comes down to confidence - the more you win the more confident you are.
"We'll get on and make sure we win the series. We've got to make sure we get
focused and work hard ready to start in Durban on Boxing Day."
Strauss has yet to play in a losing side after making his debut in the first game of England's streak.
"In every Test match someone else has contributed, which has been fantastic.
"It's good to play alongside some very experienced and very good cricketers and that rubs off on a new player coming into the side," he said.
"Over the eight Test matches, eight different batsmen have scored 100s and that shows the depth we've got."