Tarouba (Trinidad), South Africa's pacers summoned a spell from hell to defeat a nervous Afghanistan for a disappointing 56 in the first semi-final of the T20 World Cup here.

Marco Jansen (3/16) Kagiso Rabada (2/14) and Anrich Nortje (2/7) ripped the soul out of Afghanistan's pacesetter, reducing them to 28 for five inside the Powerplay, with their innings eventually doubling at just 11, 5 overs.

Afghanistan were unable to come back from that depth as their dream of reaching their first World Cup final seemed to be over before it even began.

While South Africa's pacers were right, the Afghan batsmen should also take some of the blame for being flustered on a pitch that hid no ills apart from those long-range pitches.

Opener Rahmanullah Gurbaz was the first to perish, chasing Jansen's delivery outside off stump to give Reeza Hendricks an easy catch at slip.

The dismissal of the in-form Gurbaz appeared to inject a dose of panic into the Afghanistan line-up, and Gulbadin Naib was consumed by a delightful delivery from Jansen.

But the next two dismissals were a combination of the bowler's brilliance and the batsmen's irrationality.

Ibrahim Zadran, on whom a lot depended for the Afghans, did not move his feet at all when Rabada's delivery went a little wide. There was enough space for the ball to go past his bat and hit Zadran's leg stump.

Three balls later in the fourth over, Mohammad Nabi's dismissal was similar and the only difference was that Rabada disturbed the stump this time.

Nortje joined the party with the scalp of Azmatullah Omarzai, whose cut found Tristan Stubbs deep.

Gurbaz, Zadran and Omarzai have been the main run-makers for Afghanistan in this ICC showpiece, but on the crucial day all they could manage was just 12 runs between them.

Captain Rashid Khan, who could have made some valuable runs, decided to expose all his stumps to Nortje to see the one near his legs circling the field.

Leg-spinner Tabraiz Shamsi (3/6) delivered the knockout blow to Afghanistan's batting line-up with two wickets in one, dismissing Karim Jannat and Noor Ahmad.

At this stage, South Africa is well prepared to face the winners of the second semi-final between India and England in the title clash.