Kolkata, March 4 -- A thunderous half-century by Marco Jansen powered South Africa to a commanding 169 for eight against New Zealand in the first semi-final of the T20 World Cup at the Eden Gardens here on Wednesday.

Walking in with his side under pressure, Jansen transformed the tempo of the innings with a blistering 55 off just 30 balls, striking two boundaries and five towering sixes at a strike rate of 183.33.

After electing to field first, New Zealand landed early blows. The Black Caps brought in off-spinner Cole McConchie to test the South African top order and the gamble paid off immediately as he dismissed Quinton De Kock and Ryan Rickelton, leavingthe Proteas struggling at 12/2.

Aiden Markram and Dewald Brevis then stitched toge...