The All Blacks routed the tourists for a 3-0 series whitewash in Wales' 18th Test match since August 2015.
"Everything is raw, I am finding it hard to find the words and pick the positive aspects," said Warburton.
"If you look at the scoreboard it tells the story. We can have no excuses about it being a long season. They were far better than us, it is simple as that."
Wales could only muster two first-half Dan Biggar penalties as the All Blacks ran in six tries without reply.
"New Zealand have been outstanding and deserve the win over the last three Tests," added Warburton.
"It was poor today. In the first half our kick chase was bad, our defence was not good enough. We are making basic mistakes that you can not get away with over here.
"The first two games we thought we played pretty well, just a couple of errors, but we were poor today.
"Basic mistakes like that you just can't do over here and we were definitely second best."
All Blacks captain Kieran Read was delighted with his side's improvement on the first two Tests, which they won 39-21 and 36-22 respectively.
"I am extremely happy with the way we have stuck at it. Against a pretty good Welsh side, to get a 3-0 result is pretty pleasing," said Read.
"We came out today and showed a lot better intent, we looked after the ball and it was nice to put pressure on them.
"It takes time against quality sides to wear them down, we managed to do that and started better than last week.
"It is the start of the year and we have a new group.
"We will celebrate the series win and get back to our franchises and go again."
Captain Sam Warburton says there were no excuses for Wales' 46-6 third-Test defeat by New Zealand.