The new Canaries boss has taken five points from his first three games since replacing Daniel Farke last month.
They go to Tottenham on Sunday second bottom of the Premier League and three points from safety.
Krul helped his side to a 1-1 draw at former club Newcastle on Tuesday and feels the Canaries’ mindset has changed.
“We’re also showing a bit more belief. That’s the big word, we now believe we can stay in this league,” the goalkeeper said. “We’ve worked so hard get to this league and we’re fighting every day to prove that we can stay in the Premier League.
“I think the confidence we’ve taken from the last few games shows us that we can be competitive in any game.
“We don’t have to be scared but we have to be respectful because we’re playing against a top team.
“Defensively, we’re definitely more solid and that’s not just as a defensive unit, that’s as a team.”
Norwich have beaten Tottenham just once in their last eight league meetings but knocked them out of the FA Cup on penalties in 2020.
Antonio Conte’s men beat Brentford 2-0 on Thursday and Krul knows, despite captain Harry Kane scoring just once in the Premier League this season, Spurs remain a potent attacking threat.
“(Harry) Kane and (Heung-min) Son are amazing players. I know I’m probably going to busier than the last few weeks, so you have to prepare in the right way,” he told the club’s official website.
“With these top strikers, they can hit you with shots from any angle at any time so we’ll have to be on our game as a defensive unit.
“I’m excited for the challenge. It’s a beautiful stadium and it’s another exciting challenge for us as a club.”
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