Drew Mitchell grabbed two opportunist first-half tries as the Barbarians inflicted a 26-20 defeat on South Africa at Twickenham.
The Springboks, fielding only three of the side who started last weekend's 21-11 victory over England at the same venue, were run off their feet in the first half as the all-star Baa-Baas turned on the style.
James O'Connor contributed 11 points for the Barbarians, including a first-half touchdown, while Quintin Geldenhuys scored a try in the 62nd minute.
Odwa Ndungane scored a try early in the second period for South Africa but they had to wait until the 70th minute for the second through Bakkies Botha.
They scored another in the final minute, Bandise Maku touching down, with Elton Jantjies kicking the rest of their points.