Pietersen hit 108 not out off 96 balls and enabled England to post 270 for five after they were surprisingly sent in on a good batting pitch.

Playing in his sixth one-day international, Pietersen, 24, celebrated his maiden century by repeatedly kissing the England badge on his helmet.

It was an emphatic riposte to South African crowds who have given him a hostile reception after he made some outspoken comments about his allegiance to his adopted country.

Pietersen was not originally selected for the series in South Africa but was called up after some impressive performances in his debut series in Zimbabwe last November.

Wednesday's innings took his total of international runs to 234 in five innings. He has only been dismissed once.

The hard-hitting Pietersen, who started his first-class career for KwaZulu-Natal in South Africa before taking advantage of a British passport to play county cricket for Nottinghamshire and qualify for England, shared stands of 80 with skipper Michael Vaughan (42) and 92 with Paul Collingwood (40).

England made a flying start when Marcus Trescothick and Geraint Jones put on 52 for the first wicket in 10.1 overs but the South African bowlers then pegged back their opponents, who struggled to 67 for three before Vaughan and Pietersen came together.

The pair started cautiously but kept the score moving with brisk running between wickets before picking up the tempo as the South African bowlers wilted in sweltering heat. Pietersen reached his fifty off 55 balls and his century off 91. His innings included six fours and two sixes.

South Africa made two changes from the team that was beaten by 26 runs on the Duckworth/Lewis me-thod in the rain-interrupted first inter-national in Johannesburg Sunday.

Batsman AB de Villiers, who was surprisingly omitted after making 92 and 109 in the final Test last week, was selected to make his one-day international debut in place of Adam Bacher, while seam bowling all-rounder Andrew Hall was preferred to left-arm spinner Nicky Boje.

England picked an unchanged team for the day-night match.

Although teams chasing targets have a good record in Bloemfontein, and England have been better at chasing than defending, it was a surprising decision by South African captain Graeme Smith to field and not to take advantage of ideal batting conditions. South Africa have lost 11 of their last 12 one-day internationals.