June 10 (Reuters) - South Africa became the first team to qualify for the T20 World Cup Super Eight stage as spinner Keshav Maharaj defended 11 runs off the final over to help secure a nail-biting four-run victory over Bangladesh in a low-scoring Group D clash on Monday.

South Africa won the toss and elected to bat on another difficult wicket in New York, the third day in a row the same pitch has been used, and limped to 113 for six in their 20 overs having recovered from 23-4.

Heinrich Klaasen (46) and David Miller (29) put on 79 for the fifth wicket, a record for South Africa in T20 World Cups, to get their total past the century mark against excellent Bangladesh bowling.

The sub-continent side also found scoring difficult but when Towhid Hridoy (37) put on 44 for the fifth wicket with Mahmudullah (20), they looked on course for their first victory over the South Africans in T20 cricket.

But when Hridoy departed the scoring rate slowed again and, needing six from the final two balls, Mahmudullah was a metre away from clearing the rope but caught on the boundary by Aiden Markram as Maharaj finished with 3-27 in his four overs.

South Africa have three wins from their three games in the pool, all on the two-paced uneven New York wicket, while Bangladesh have a win and a defeat from their two fixtures.

(Reporting by Nick Said; Editing by Ken Ferris)...