Things were completely in SiriLankan hands and they can easily revert results in thier favor but thier batting collapse were just horrible, because from a winning and dominance side within blink of eye they goes downward and become defeating side. At the moment when they required 90 around just like you mentioned SiriLankan just lose a single wicket and having huge number of wickets. but still they unable to goes even closer to required like with more than 40 runs margin they lose the second match of the series and thus lose the t20 series by 2-0 which I believe will be turn into 3-0 in last match
However, the result of the match was expected for me and from my personal perspective, I also think that most people expected New Zealand to win this match as well. However, I will agree with you that Sri Lanka's wickets fell a little too quickly, especially when it came to taking the last wickets here, with two outs almost every over. In this regard, New Zealand's batting lineup has also performed excellently, with Jacob Andrew Duffy in particular having a hilarious performance as a T20I fielder.
Anyway, New Zealand has already won the series, so what are your thoughts on match number three? I expect that since New Zealand are the hosts in this series, they will enjoy the advantage in the third match as well and whitewash the Sri Lankan team.