New Zealand's captain Kane Williamson has described winning the inaugural World Test Championship in Southampton as a "special feeling", but would not go as far as calling it the biggest day in the history of New Zealand cricket.

"Certainly is a very special feeling. A couple of close ones and then to get one [final win is special]," Williamson said before collecting the Test Championship trophy. "India are a formidable side and we knew coming into the game it was going to be an incredibly tough challenge.

"It's the pinnacle, isn't it, being involved in the final," he added in the post-match press conference. "Even coming into the last day, although it was staggered with the weather and all the delays that we had, all results were on the table. It was just great the heart the team showed to take it across the line.

"We saw both teams grab the momentum at certain points in time, and then to have the sixth day as back-up made for a fantastic game to be a part of. For us it's a very proud moment in our history and a proud moment, just as a team really, to stick to what we do well and come away with the win, which is a really great feeling."

After the heartache of consecutive World Cup finals in 2015 and 2019 - the latter an agonising loss on boundary countback after both the match and the subsequent Super Over were tied - the triumph was sweet vindication for a New Zealand squad that has arguably never been bettered in the country's history. Williamson, however, was keeping his emotions in check.

"It's a very special occasion and a fantastic feeling," he said. "We've been involved in a couple of finals previously, and I suppose the first one [2015] was one-sided, the second one was pretty interesting, and this feeling is a bit different to those, which is great. I know the guys will celebrate that.

"2019 was a great occasion and a brilliant game of cricket as well," he added. "But obviously it's a slightly different feeling, being on the right side of the result for us, and also a part of a great game of cricket and a great occasion, the first official World Test Championship. This is a really good feeling."

Williamson also said that while 11 people took the field for the WTC final, he wished to pay tribute to all 22 squad players who were part of the New Zealand Test side in the championship cycle. He also said that it was his players' "heart and commitment" that earned them the final win.

"I think for us, we know we don't always have the stars, and we use our bits and pieces to stay in games and be competitive," Williamson said. "I think we saw that in this match. I think we saw a lot of heart, a lot of commitment. What's important to our group is our commitment to our style of cricket. And we had to, we know how strong this Indian side is in all conditions. We've seen it for a long time.

"It's not always easy I suppose when you're playing in a one-off Test match as a final where anything can happen, and it's a fickle game, and we respect that, but yeah, throughout all six days it ebbed and flowed and no one really got the upper hand for a long period of time."

The key partnership on the final day was Williamson's unbeaten 96-run stand with Ross Taylor, who struck the winning boundary to finish unbeaten on 47. The pair first played together in Williamson's Test debut back in 2010, also against India in Ahmedabad, and the captain paid tribute to his veteran batter.

"It was fantastic to be a part of a partnership like that," he said. "Obviously Ross is our most experienced player and a leader in the group, so it was nice that we were able to soak up some of the pressure and then score a few together, although it was really difficult to come by. But having an experienced hitter like Ross out there was certainly helpful.

"It was a really special feeling to be there at the end together and tick those runs off. Even though it was 130-odd, on that surface you never felt comfortable. It was nice to soak up some of that pressure and put together a partnership."

Williamson also praised his lower-order batters in the first innings, who helped New Zealand take a 32-run lead. He said that while he personally found it tough to score runs against an "amazing" Indian attack, the way the lower order played with the freedom to take them to the lead played a big role in New Zealand eventually winning the match.

He also praised the surface prepared for the final, calling it a "sporting wicket" for providing a result despite only four days of cricket possible.

"That was tough obviously, an amazing attack, didn't give you much to hit for long periods," he said. "It was certainly tough going but we had to apply ourselves and the lower order played with a bit more freedom to take us closer to some sort of lead, which was important on a wicket like this. A very sporting surface, I suppose, and only four days of cricket produced some result."

The result, while a disappointment for India, was warmly greeted by the final's neutral viewers around the world, who have taken to New Zealand's style in recent years - starting with Brendon McCullum's commitment to attacking cricket, and continuing through Williamson's five-year tenure, including his grace in defeat in 2019.

But after it was suggested on the match commentary that 'nice guys do finish first sometimes', Williamson insisted that the team's only aim was to remain true to themselves.

"In terms of our team and our behaviours, we try and commit to what's important to us," Williamson said. "People can comment on that, or tag us how they'd like, but it's not about being anything other than authentic to us as a group and the sort of cricket that we want to play, and the behaviours that are important to us day in, day out. That's something that is important to us as a team."