Eddie Howe admits he is concerned that player confidence levels have been "damaged" by their FA Cup exit against Cambridge.
The Magpies now face what Howe himself describes as "season-defining" fixtures at home to Watford and away to Leeds later this month.
Howe's side were denied by the woodwork and a goalkeeper in form in Dimitar Mitov who kept out Joelinton at the death and Jacob Murphy.
Go here for all the latest Newcastle United news
Howe emerged to say after the game: "We are desperately disappointed.
"We really prepared well for this game and we played a very strong team.
"But ultimately we found a goalkeeper in superb form and a team that defended for their lives and we couldn’t break them down.
"I don’t think there was anything wrong with our attitude we just couldn’t deliver the quality to score.
"We did have some good moments but we lacked that killer instinct that every team needs."
But regardless of the disappointment the season boils down to those two vital clashes against Watford and Leeds.
Howe added: "The size of the task remains what it is, I just hope the game doesn’t damage our players’ confidence.
"The next group of games could potentially be season-defining.
"Giving them the confidence to execute is the challenge I face.
"It’s a good group of players with a good attitude but we have to take this defeat on the chin and come back again."
For the latest Newcastle news direct to your inbox, go here to sign up to our free newsletter
