Mikel Merino is used to playing in front of sell-out crowds from his time at Dortmund.
However, the Pamplona-born player was still taken aback by the atmosphere” at his new home.
Merino added: “It was crazy all the people supporting the team and they way they sang and supported us.
“It was really, really good. It’s an extra thing for us. It’s an incredible plus for us.
“Every team that comes here to play will feel it.”
Merino is quickly learning about the demands of English football.
On the Premier League, he said: “It’s a top league where each week you can play against really big teams, like Tottenham.
“The rhythm, the way they ran and pressed ... you have to give 100%. If not, you will lose.”
Shelvey’s dismissal changed the game against Tottenham, who took control when Newcastle went down to 10 men.
And Merino believes he and his team-mates can take encouragement from their performance against Mauricio Pochettino’s side, who finished second in the Premier League last season.
“It was a tough game,” said Merino.
“We’re not happy about the final result. I thought we competed really well.
“The team deserved at least a draw, but things didn’t go as we expected.
“They are a really good team, but we have to have the idea that we have worked really well. We have to keep working like this.
“We did an incredible effort in the first half and also in the second half with one man less.
“We did a really good job. We have to keep going. We are going the right way. If we keep working like this, things will come.”