The 28-year-old England vice-captain said: "We stood up and played our brand of cricket under that pressure.'
Chester-le-Street: England's Jos Buttler said he felt a sense of relief as well as excitement after the tournament hosts booked their place in the semi-finals of the World Cup.
Back-to-back defeats by Sri Lanka and reigning champions Australia, which followed an earlier group-stage loss to Pakistan, threatened to scupper England's bid to win a first World Cup title.
But they responded in style with a 31-run win over India followed by Wednesday's 119-run thrashing of New Zealand in Chester-le-Street that saw them into the last four from the 10-team group phase.
"It feels great. We're excited and have a bit of relief as well," said Buttler after England reached their first World Cup semi-final since 1992.
"It's obviously been two tough games to finish to qualify, and we showed great character to come through with two very good performances."
England have spent much of the past two years as the world's top-ranked side in One-Day Internationals and Buttler said: "We are just very excited to be in a semi-final. From the start, I think it was the minimum requirement, the first stage we had to get to."
The 28-year-old England vice-captain added: "We stood up and played our brand of cricket under that pressure.
"That breeds a lot of confidence for the group, that our way is the best way and gives us a lot of chance of performing. That's what we have resorted to in the two must-win games and shows that we must continue that."
Since his century against Pakistan a month ago, Buttler's batting has gone off the boil but the wicketkeeper contributed to England's win over New Zealand with a brilliant diving catch to dismiss Martin Guptill.
"I've been a bit disappointed not to have contributed as much as I'd like. I haven't quite executed or made the right decision and have found ways of getting out," said Buttler.
"Luckily I still have another chance for another innings or two in the World Cup."