Stand-in skipper Rohit Sharma said his side wanted to bat in tough conditions as part of their preparation for the upcoming World Cup and hence chose to take first strike in the fifth ODI.

Rohit said despite knowing that the Westpac Stadium pitch would aid the fast bowlers, he decided to bat first after winning the toss.

"I had a look (of the pitch) before the toss and knew that there was moisture, which would be helpful for the fast bowlers initially. As a team we wanted to see how we face the challenges because come the World Cup we will be put into those situations, so what then," Rohit said at the post-match conference.

"Yes, we lost four wickets upfront, there is a learning there for us as how we should bat when the ball is swinging and conditions are not easy. The guys now know come the situation how to do it. The run rate was not great in first 30 overs but we still managed to get to 250, which is a big positive," he added.

The 4-1 scoreline is India's biggest series win on New Zealand soil across formats since they started touring the country in 1967, and Rohit said it was a "massive" achievement.

"Coming here and beating New Zealand 4-1 is a massive achievement. They play very good cricket, so it is a great take away for us. Last time we were thrashed 4-0. We didn't have a point to prove but we just wanted to play good cricket, which we have been doing for the past 8-10 months now," Rohit said.

"New Zealand have got great balance. They bat deep and have a quality bowling line-up, we saw a bit of glimpse of that in last game where they challenged us, so for us 4-1 is a great achievement."

India's batting came a cropper in the fourth ODI in seaming conditions in Hamilton as they were dismissed for 92 and eventually lost the match by eight wickets.

On Sunday also, India were staring at another sub-100 total after being reduced to 18 for 4 before a middle-order fight back saw them post 252. The 98-run stand for the fifth wicket between Ambati Rayudu (90 off 113) and Vijay Shankar (45 off 64) was the highlight of the middle-order fight back.

Rayudu produced one of his best innings to help India post a competitive total and Rohit said it will boost his confidence ahead of the World Cup.

"It would be a massive confidence boost for him (Rayudu) to bat in that situation. At 18 for 4, you need to bail the team out. He has been around for many years and he used his experience well. He is looking very good and I just want him to continue. We have five more games against Australia back home, so if he bats the way he batted, it would be good for us," he said.

"I won't be able to comment who would bat at No. 4 in the World Cup but talking about the series, he can take a lot of confidence from the series, he finished off games for us."

Also praising Shankar, Rohit said, "Vijay batted brilliantly and I'm disappointed that he got out unfortunately, he should have got a 50 or even a 100 may be."

India fielded two fast-bowling all-rounders in Hardik Pandya and Shankar for the first time and Rohit said they wanted to try out as many combinations possible ahead of the World Cup.

"We want to be very well prepared for the World Cup, so we wanted to try out all our combinations. If the series was on line, we would have played with two spinners and three seamers and Kedar being there, but with the series won, we wanted to try out combination," he said.

"Because we will be playing nine games in World Cup, and anything can happen, injuries, being out of form, so we wanted to try our every combination."

The stylish opening batsman also lauded Kedar Jadhav, saying his presence provides balance to the team.

"Kedar gives us that balance being a second spinner. I consider him a proper spinner because every game he bowls 6 or 7 overs and gets a wicket as well. Even today, the wicket of Kane Williamson, it was a crucial point. He came and broke that partnership," he said.

Young Shubman Gill could not grab the two opportunities that he got in the last two ODIs but Rohit said the lessons learnt here will go a long way in his career.

"He is a real good talent, with just two odd games, you can't judge. This will give him a lot of learning. He is a top order batsman, he will be in those type of situations where ball is swinging around, so it will help him. He has done well and I don't find any reason why he can't play longer for India."

New Zealand captain Kane Williamson meanwhile said that there are a lot of lessons for his team to take from the series.

"In the end, they got just above par I felt. We lost way too many wickets, the scoring rate was always under control, " said Williamson.

"Me and Latham could have taken the partnership deeper there but their bowlers bowled with great accuracy. India have taught us a few lessons throughout the series and we need to learn quickly. It's a game of pressure and throughout the series, we were under pressure more than they were."

Ambati Rayudu was named man-of-the-match for his 90 and he said that aim was to just bat the 50 overs after the loss of early wickets.

"I wanted to take the game to the 30th over without losing another wicket, we knew that we were up against a quality bowling attack," said Rayudu.

"The aim was to play full quota of 50 overs. People batting at four, five, six get chances only in tough situations but we might face similar challenge in the future. It was a great effort by our bowlers."