I think I would say both are valid: batsman in pressure and bowler did the god job making most of it. But if I were to pick one with more weight then I would give Shami the credit since 2 runs is easy and he really did a very good job indeed.
I also thought it will go out of hand when NZ scored 17 but Sharma proved me wrong.. Not many can hit back to back 6 on the last balls and with that much pressure- in front of such crowd..Whuff!!! well done Rohit...
Yeah, even the bowler goes wrong so many times. Have seen Sharma giving 23 runs in the last over that too during a WC match in 2011. Rohit even mentioned that it was his first super over and hence he panicked at first and went for the second run when not needed. NZ deserved to win even the WC last year but we all know what happened.