"Ireland have been playing some good cricket. I've been watching a few of their games and they look a good side," said the 21-year-old Essex player ahead of the Providence stadium clash here on Friday.
"They've already proven they can beat some of the top sides in the world and the main thing for us is to be on top of our game when we face them. We may be expected to win, but we all know that cricket doesn't work like that."
Ireland, who qualified for the World Cup after finishing second in the ICC (International Cricket Council) in 2005, shocked the cricket world by defeating former champions Pakistan in the first round.
They tied their first Group D match against Zimbabwe before losing to the hosts West Indies in their last match.
England, who like Ireland carry no points from the first stage, qualified for the second round with wins over Kenya and Canada and a defeat against fellow Super Eights qualifiers New Zealand.
England are playing in the last eight for the first time since 1996.
Bopara said England are targetting a place in the semi-finals with renewed confidence.
"We played well in the last couple of games in the group stages and we are feeling confident going into the Super Eights," said Bopara, who played against Canada after England decided to punish all-rounder Andrew Flintoff for late night drinking.
"It's always a great feeling to go out and play some games and I am feeling good, I am feeling confident and I am just enjoying myself.
"I had a decent game against Canada and I felt good with bat and ball and it was a good team performance against Kenya, it was very solid and I didn't really have to do much," said Bopara, who scored 29 and took 2-43 in England's 51-run win at St Lucia.
He was required to bowl only one over and did not bat in team's seven-wicket win over Kenya in a rain shortened match at the same venue.
Bopara said England has done well in one-day cricket recently and has the confidence to move on.
"We are very confident, there's plenty of energy in the group and we're feeling good about ourselves - we can't wait to get on with it.
"If we just think back a few months ago to the Commonwealth Bank Series in Australia we beat the number one team in the world so I don't see any reason why we shouldn't reach the final," said Bopara of England's tournament win last month.