The Magpies entertain Ukrainian side Metalist Kharkiv at St James' Park on Thursday night having steadied the ship in the Premier League with two victories in their last three games.
They remain too close for comfort to the Barclays Premier League relegation zone, but, with five January signings on board and spirits soaring as a result of their recent recovery, the prospect of fighting their way into the last 16 of a European competition is one they can attack with confidence.
Krul said: "We have had a really hard time during the first half of the season, but with these new faces coming in, it gives us a massive boost and a lot of confidence.
"We have still got a lot of hard games to play, but we can go into those games with a lot of confidence."
The arrivals of Mathieu Debuchy and Moussa Sissoko in particular have given the club a lift, and although the former, like striker Yoan Gouffran, is ineligible in Europe, the mood they have helped to create is hugely positive.
Krul said: "They have been fantastic. Normally you see with new players, they take a bit of time to settle. But these lads, from the moment they walked into the club, they have been great for us."