New Zealand''s Finn Allen blasted the fastest century in T20 World Cup history in Kolkata on Wednesday as his side hammered South Africa by nine wickets to reach the final.

Chasing 170 to win the first semi-final, Allen hit an unbeaten 100 off just 33 balls, to obliterate the previous mark of 47 balls by Chris Gayle, as New Zealand raced home with 7.1 overs to spare.

Allen went on a rampage as he finished with two fours, two sixes and a four off successive balls to hit the winning runs and reach his hundred with a roar of delight at Eden Gardens.

Tim Seifert hit 58 in a 117-run opening stand with Allen off just 9.1 overs to set up the victory romp.