Two goals from Ayoze Perez, one from Christian Atsu and Matt Ritchie’s penalty gave the Magpies the victory they needed for promotion against Preston at St James’ Park.
The visitors played the last 30 minutes with 10 men after skipper Paul Gallagher was sent off for a diving save with his hands on the line.
Ritchie admitted the Newcastle players’ joy was mixed with relief.
“I think so, yes,” he said.
“It has been a little bit tense here at times but we always believed.
“It is disappointing to be where we are [second] because a few weeks ago we were top of the league.
“But if we win against Cardiff on Friday then we can put a bit of pressure on leaders Brighton.”
Newcastle skipper Jamaal Lascelles also emphasised the importance of going on to win the title.
“Of course it matters,” he said. “That’s what we have to go for now.”
