Berdych didn't choke this match. He maybe chocked the tiebreak, but it was obvious from the very start Nole would win this match like he won 10 of the last 11.
Nole was toying with Berdych in the first set, he was perfect. Then he lowered his form in the second like he usually does and Tomas stepped it up. But Nole was never in danger of losing this match.