The Three Lions go into the Wembley double-header knowing that two wins will guarantee a place in Rio next year but their only qualification victories so far have come against minnows San Marino and Moldova.
Rooney, though, has no doubt Roy Hodgson's men will get the job done against Montenegro on Friday night and that they will be toasting a successful campaign when the final whistle blows following next Tuesday's encounter with Poland.
"We're going to do it. We're going to get to the World Cup," he told national newspapers.
"I'm confident, we're confident, but you always have to be sure you're not over-confident. These are going to be two tough games for us, but we're good enough to do it."
He added: "Would it be unthinkable not to get to Rio? Of course, this is crunch time.
"They are going to be two tough games, though, because Montenegro and Poland are good sides and their best qualities are on the counter attack.
"We will have to try and break them down and make sure we don't get caught out at the back. I think we'll do it, but nobody should think it's going to be easy."
Rooney has also declared himself fighting fit after sustaining a minor injury while playing for Manchester United in Saturday's 2-1 win over Sunderland.
"I've got a little knock but I'll be fine for England," he said.
"I can't wait to be honest. As soon as the Sunderland game had finished, I started to think about England."
United fought back from a goal down against the Black Cats thanks to two goals from Belgian 18-year-old Adnan Januzaj who could be eligible for England one day on residency grounds.
And Rooney admitted he would welcome his club-mate into the international fold should his availability come to fruition.
"He's been here since he was 16, but I'm not sure of the rules," he said.
"I'm sure the FA will be doing everything they need to do to get him to play for England.
"It's not down to me, but hopefully, I don't know."