I think Sri Lanka is focusing only on test matches, because they always made a good performance in test matches since the previous year started, beaten to Pakistan and New Zealand very well that was a really unexpected results but now they are just trying to maintain good results in all formats but somehow cannot achieve it.
However, already Sri Lanka lost the series but they won the last match. At least they have something to cheer about at the end of the series but that changes nothing about the Sri Lanka's bad performance in the whole series.
The result of last ODI showed that Sri Lanka is not an ordinary side and must not be taken as for granted. Also if Sri Lankans have the potential which they displayed today then why not they showed it in first two games, why they waited for 2 consecutive loss to regain the form. Sri Lankans were in complete command of the game today, first in batting they scored 290 runs and then in bowling they didn't allowed New Zealanders to score runs. Chapman was the only New Zealanders who score runs today but his knock was not enough because of no support from other end.