Pakistan scored the most in their last six games in the UAE by setting New Zealand 167 runs to win. The Kiwis had a nervous start but were at an acceptable 96/3 at 12.2 overs. Then, Pakistan showed why they're famous for their bowling.
After Williamson lost his wicket, these are the scores of the players who got out: 26, 2, 0, 0, 7, 1, 1. In fact, poor Williamson scored more runs than the rest of his team combined. He scored 60; the entire team was out for 119. They had to play scoring shots because the run rate was creeping up but they simply couldn't handle the bowling.
This sets up the ODI series really well. New Zealand has a lot of batting firepower while, now, Pakistan has a strong bowling unit and an improving batting lineup.