After winning the toss and electing to bat first, Sri Lanka got off to a good start thanks to Avishka Fernando and Kusal Mendis. However, their partnership was broken in the fourth over when Fernando was dismissed for 10 runs. Mendis continued to bat well, reaching his half-century, but was eventually caught by Seifert off the bowling of Todd Astle.
Sri Lanka's middle order struggled to make an impact, with only Dhananjaya de Silva reaching double figures apart from Mendis. The hosts finished their innings on 161/9, a below-par total on a pitch that seemed to favour the batsmen.
New Zealand got off to a flying start in their chase, with openers Colin Munro and Seifert putting on a 79-run partnership in just 7.3 overs. Munro was dismissed for 13 runs, but Seifert continued to bat aggressively, hitting six sixes and four boundaries in his knock of 84 runs off just 43 balls.
The Kiwis suffered a minor hiccup when Seifert was dismissed in the 13th over, but Ross Taylor and Colin de Grandhomme steadied the ship with a partnership of 41 runs. Taylor was dismissed for 48 runs, but de Grandhomme and Daryl Mitchell finished the job, taking New Zealand to their target with four wickets and 25 balls to spare.
Sri Lanka's bowlers struggled to contain New Zealand's batsmen, with only Isuru Udana managing to take two wickets. Lasith Malinga, the home team's captain, went wicketless, conceding 28 runs in his three overs.
New Zealand's victory in the second T20 international match of the series means that they have already won the three-match series with a game to spare. Sri Lanka, on the other hand, have lost their last seven T20 international matches, a worrying trend for a team that has struggled in the format in recent times.
The third and final T20 international match of the series will be played on September 6 at the Pallekele International Cricket Stadium. Sri Lanka will be looking to salvage some pride with a win in the final match, while New Zealand will be hoping to complete a whitewash of the hosts.
Overall, it was a dominant performance from New Zealand, with Tim Seifert's impressive knock and their bowlers' tight spells making the difference. Sri Lanka will need to regroup and come up with a better performance in the final match if they are to avoid a whitewash at the hands of the Kiwis.