South Africa’s Kruger moved to 13-under par at the halfway mark at Leopard Creek Country Club, clear of a three-way tie for second consisting of Scotland’s George Murray, Englishman Seve Benson and Felipe Aguilar of Chile.
Kruger took advantage of a late slip-up by compatriot George Coetzee, who led by four before he dropped five shots in his last three holes to fall back into a tie for seventh.
Seeking his first European Tour title, Kruger had an eagle, five birdies and two bogeys to move ahead after sharing the lead with Benson after the first round of the ?1-million ($1.3-million) tournament in northern South Africa.
Benson had three birdies and two bogeys for a 1-under 71.
Two-time defending champion Pablo Martin of Spain failed spectacularly in his quest to become just the fifth man to win a European Tour event three times in a row.
Hoping to join an exclusive list that includes Ian Woosnam, Nick Faldo, Tiger Woods and Ernie Els, the 2009 and 2010 Alfred Dunhill champion finished tied for last place after two rounds, shooting 81 and 82.
Martin had four double-bogeys and four bogeys on Friday for a 19-over 163 two-round total.
Coetzee’s slump was nowhere near as dramatic. But it did rob the highest-ranked player at the event of a place among the leaders when he went double-bogey, double-bogey, bogey on Nos. 7, 8 and 9 – his 16th, 17th and 18th.
Kruger followed his eagle on the par-5 second with successive bogeys, but recovered to string together four birdies without dropping a shot coming in.
“I didn’t have fun in the early part of my round, but later I did have fun,” Kruger said. “I think you should have fun, otherwise, why play? If you enjoy it you tend to play better.”
Benson was subdued after eight birdies landed him his best round on the tour on Thursday, while Murray stayed in contention with a solid 69 after his first-round 66.
Aguilar was one of the biggest movers at Leopard Creek, soaring to an 8-under 64 with eight birdies to jump up into a tie for second after opening his tournament with a 71.