Sri Lanka have lost in the first two matches which means there is a high chance of Sri Lanka losing in the third match as well. That is, whether Sri Lanka can save themselves from being whitewashed, it will be understood in the third match. Sri Lanka lost the first match by a narrow margin but Sri Lanka lost the second match by a huge margin of 45 runs. If Sri Lanka plays the third match with the same squad then there will definitely be more chances of defeat in the third match as well.
Yes, You are right It is very important for Sri Lanka to win the last match if they want to avoid the Whitewashed. New Zealand has had a very outstanding performance in the first two matches and very likely they are favorite to win last one. Sri Lanka lost the first match because of their mistake, if they had won the first match the series would have been level. The last match and the series will be played in the morning. Sri Lanka needs to changes his batting order and make some changes in playing XI if they want to scored huge run on board. I hope that the Sri Lankan team will make a comeback in this and win this match to avoid being whitewashed.