India ticked all the boxes when it mattered the most and crushed South Africa in the must-win third T20 international to stay alive in the five-match series here Tuesday. Yuzvendra Chahal (3/20) and Harshal Patel (4/25) led the way with the ball after sizzling half-centuries from Ruturaj Gaikwad (57) and Ishan Kishan (54) powered India to 179 for five.