Most of the T20 games that are played end up being a close contest between bat and ball. Fortunes change very quickly in a T20 game, sometimes even with a single delivery. Here is a compilation of 10 such deliveries that decided matches. Since they happened during the World Cup, they had a say in the tournament, as well.
#10 Morne Morkel to Umar Akmal (Pakistan vs. South Africa, Colombo, 2012)
Chasing 133 to win, Pakistan needed 9 runs off the final over with two wickets in hand and Umar Akmal at the crease. Morkel faltered and bowled a juicy full toss the second ball, and Akmal was quick to send it out of the ground: it was the killer blow. Pakistan won by 2 wickets, with 2 balls left in the game, and proceeded to the semi-finals.