Fabio Capello's men laid to rest the ghost of previous defeats to Croatia, who beat them twice in their last campaign.
Wayne Rooney, who had a hand in all of Walcott's goals, struck the other.
And Walcott told Setanta Sports: "There were 11 stars, the whole team were stars today.
"We showed everyone how strong we are as a unit. We proved it tonight, it was brilliant."
As for his own excellent contribution, Walcott said: "The first two goals were similar - I tend to cross those a lot but thought I'd be a bit more greedy this time. For the second goal, it was a great ball by Wayne Rooney.
"You've always got to put 100% in. I'm grateful he (Capello) has given me the opportunity, I've got to take that forward now and keep on improving."
Fellow goalscorer Rooney praised Walcott for his impact.
"He offers something a bit different. He is probably the quickest player I have seen," he told Setanta.
"He showed glimpses against Andorra and he scored three great goals tonight.
"Sven-Goran Eriksson saw the talent in him in selecting him for the 2006 World Cup. It has been a bit of a roller-coaster for him the last two years."
Rooney also admitted, after two defeats to Croatia cost England a place at Euro 2006, the victory felt all the more sweeter.
"Tonight was a bit of revenge. It was a great performance and a great result," he added.
"You always enjoy a 4-1 victory, especially after what Croatia did to us in the last qualifying campaign."
Captain hailed Walcott's form in the international double-header as "awesome".
"I think the gameplan was to go out there and not give anything away in the first 10 or 15 minutes and assess the game, which we did tonight," he told Setanta Sports.
"We came into this match confident, but not over-confident. We respected them as individuals, respected their record at home.
"It's fantastic to hear the fans singing, hopefully that will get them behind us even more now."
As for Walcott's input, Terry said: "When he's on the teamsheet defenders are petrified, and I think we saw that tonight. He gave the manager food for thought.
"I think he has set the tone in these last two games and if he continues playing like that, I'm sure he'll be in the team.
"Credit to the manager for that, credit to Theo for stepping up to the challenge. He's been awesome all week, he has come in, got involved and that performance showed what he's all about tonight."
Capello felt part of the key to the victory was having the squad together for a period of time.
"The secret is we stayed 10 days together. Today we played with a lot of confidence and without fear from the first minute," he told Setanta Sports.
"Usually when England play away they don't always have courage, but confidence and courage is very important.
"I am not surprised. I know the players. I know what is possible to do during the game and I know very well the players in training and we played today like we played in training. The same confidence, the same way without fear.
"The score is incredible but the performance of the team is very good. The players played very well, a little mistake only when they (Croatia) scored the goal."
Capello also said Walcott, whom he selected over the vastly more experienced David Beckham, had a bright future for England.
"He is young, he is a dangerous player for defenders. I am happy for Theo. You have to decide, choose one from two, and I chose right this time," he added.
"He is one of the most important young players in England. I hope he does not get injured."
by espnstar.com
