The Magpies were knocked out in the last eight of the competition by Portuguese giants Benfica on Thursday, despite a battling display.
And the 25-year-old Dutch shot-stopper feels that confidence is high in the camp as they prepare to face Paolo Di Canio's strugglers on Sunday.
"There's no hangover," Krul told the Daily Star. "In fact, we can't wait for Sunday because there's a lot of confidence in the side.
"Of course, there's mixed feelings going out of the Europa League.
"It was a massive night for us and such a shame we couldn't go through.
"But we gave it a right good go and were all over Benfica in the second half.
"When you give one of Europe's top sides a headache, you can take a lot out of the game.
"Normally, going out of a competition is a negative but the fans stayed behind and clapped us off the pitch so we'll be fine for Sunderland."