Two late goals by substitute Katie Chapman wrapped up a conclusive England victory in their opening group match of the Cyprus Cup tournament in Larnaca.
Hope Powell's team were in charge from the early stages and brushed aside a team that sit 48 places below themselves at 58th in the world rankings.
South Africa had to play the final 20 minutes with 10 players after having Nompumelelo Nyandeni sent off for two bookable offences.
But by the time the midfielder saw red the South Africans were already well beaten with England four goals ahead and cruising.
National Coach Powell said: "It was a comprehensive performance and we came through a test against an unknown quantity having never played South Africa before.
"We spent the first 10 or 15 minutes in our own half, but the girls adapted well to the opposition's style and in the end we were worthy winners with some good goals."
Captain Fara Williams opened the scoring, sliding the ball home from an 18th-minute headed pass by her Everton team mate Jill Scott.
The lead was doubled 60 seconds later as Boston Breakers full back Alex Scott crossed for Chelsea striker Lianne Sanderson to score from close range.
Striker Kelly Smith, who like Scott has just left Arsenal for Boston Breakers, hit the third goal with an angled shot three minutes before the interval.
Nine minutes after the break Leeds Carnegie defender Steph Houghton recorded her first England goal, a header from substitute Rachel Yankey's corner.
Before and after Nyandeni's subsequent dismissal England should have had more goals but had to settle for Chapman's double in the final four minutes.
The Arsenal midfielder's first goal was a close range effort, but in stoppage time her second was a 25-yard screamer.
England now face France, ranked eighth in the world, in their second Group A game on Saturday and Powell said: "This is going to be a real test for us.
"The last time we played them we drew 1-1 to qualify for the 2007 World Cup finals and knock them out, so they'll want to rectify that.
"It should certainly show us how far we've developed since that game in France, but we are looking forward to the game after making a good start to the tournament."
England (4-2-1-3): Chamberlain (Chelsea); A. Scott (Boston Breakers), Stoney (Chelsea), Asante (New York Sky Blue), Houghton (Leeds Carnegie); Williams (Everton), J. Scott (Everton) (sub Chapman (Arsenal) HT); K. Smith (Boston Breakers) (sub Westwood (Everton) HT) (sub Buet (Chelsea) 72); Carney (Chicago Red Stars) (sub Clarke (Leeds Carnegie) 62), Sanderson (Chelsea) (sub Aluko (St Louis Athletica) 74), S. Smith (Leeds Carnegie) (sub Yankey (Arsenal) HT).
South Africa (4-4-2): Mulaudzi; Dludlu; Van Wyk (Magotlhe HT); Ngwane, Mosebo; Ndimeni; Louw (Esau HT), Rammala; Nyandeni; Molatelo (Dlamini HT), Matlou.