New York, which won the first two games of the series, came up short in the bid for its first sweep of three or more games at Tropicana Field since Sept. 13-15, 2005.
But just as Strauss was set to reach his half century, he once again needlessly gifted his wicket away, top-edging an attempted reverse sweep off Hauritz to Johnson at short fine leg - the fifth time the off-spinner had claimed his wicket in the series.
Pietersen then pulled Steyn onto the roof of the Greenidge and Haynes stand and completed his 50 from 30 balls with a delightful whipped shot through mid-wicket for four, but his magnificent innings ended in the next over when a sweep off Botha looped his old adversary Graeme Smith at short fine leg.
But the left-hander fell 10 runs short of three figures when he was brilliantly caught behind by wicketkeeper McCullum attempting to paddle sweep Daniel Vettori down the leg-side.