England captain Michael Vaughan offered some words of warning to his side after sealing a 2-1 Test series triumph in New Zealand.
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News conference: England captain Michael Vaughan
"We're still not quite playing the game we can play and there's lots of improvement to be done," he said.
"We shouldn't get too excited because we've got lots to do before we can be confident of taking on the big boys.
"But we're delighted to nick the series - we deserved it - and there were signs that we can be a hard team to beat."
Monty Panesar was the fifth-day hero, finishing with figures of 6-126 as England won by 121 runs, but Vaughan reserved special praise for Ryan Sidebottom, who was named England's man of the series after taking 24 wickets.
"Ryan has bowled exceptionally well throughout the series. He's now got 50 Test wickets in a year and I'm sure there are many more to come," said the skipper.
"Stuart Broad also showed he has something special. He has tremendous character and really impressed me with how he bowled on a flat wicket yesterday. For a 21-year-old, he's a decent package."
Vaughan's praise for Sidebottom was echoed by Kiwi skipper Daniel Vettori, who said: "He was outstanding, and every time England needed a wicket he stepped up.
"I really think he was the difference between the two sides, and he'll be a real handful over in England this summer."
England coach Peter Moores claimed the win indicated a bright future for his side.
"You judge any team by how they bounce back and Hamilton was very hard to take, so the response in Wellington was great and then to back that up here in Napier was really pleasing," he said.
"I think we've found out a lot about a lot of people this year and a lot of young, new players have come in and got stuck in. The side has changed a lot and we're going through a big transition, so to win along the way of that makes it even more pleasing.
"We'll come out of the other side of this series a lot stronger. Ryan Sidebottom gives us a lot, while the likes of Stuart Broad and Monty Panesar are young and emerging.
Vaughan urged his side not to get carried away by their series win
"Outside of this team we have Matthew Hoggard, Stephen Harmison and Andrew Flintoff who I am sure will put these guys under pressure for their places.
"That sort of competitive environment can only bode well for the future of this side."
New Zealand coach John Bracewell, meanwhile, also reflected on the changing shape of his Test side, saying: "I guess the summer has ended up predictable - us winning the one-dayers and England winning the Tests.
"We kept this Test series tighter than most expected, probably by producing flatter tracks than normal, and to a point that made the games closer than the statistics suggested they would be.
"There's no denying we're going through a transitional phase in Test cricket. We needed to rebuild because of the age of the side and the injury issues we've had and I'm delighted with a lot of the guys who have stepped up.
"Overall, it's been wonderful cricket from both sides and now we're really looking forward to getting to England for the return tour in May."