But while the German described the 2-1 Premier League win as “one of the best nights we ever had”, he warned his players much better will be required in Saturday’s Merseyside derby.
It looked as though they would need to settle for another point in a stuttering start to the season, but eight minutes into added time Carvalho rifled home following a goal-mouth scramble and the roof came off Anfield.
“It’s a massive boost from a frustrating night,” Klopp said. “One of the best nights we ever had, that’s how football is.
“But we have to make sure we use these two days really well. The last two games we got six points, but we have to improve.
“It will not be that Everton open up for us now. We know it will be tough so we have to be ready.”
Only days after romping to a 9-0 win over Bournemouth, Liverpool had struggled going forward in the first half, with too many passes easily cut out by Newcastle who were then able to threaten on the counter – going ahead in the 38th minute through Isak’s impressive strike.
“I said at half-time we were forcing it too early, playing too many long balls,” Klopp added. “We looked desperate before we were. Being 1-0 down is obviously not cool but it was the least of my problems at half-time.”
The answers to those problems came from two of Liverpool’s emerging talents – the 19-year-old Harvey Elliott and Carvalho, who only turned 20 on Tuesday.
“He’s now scored twice this week,” Klopp added. “Yesterday was his birthday, he’s an outstanding player and a wonderful talent, I’m really happy for him.
“Harvey was the best player on the pitch and Fabio decided the game so I’m really happy for the boys.”
The win did come with one major concern, as captain Jordan Henderson was brought off in the second half with a hamstring injury which Klopp said must be assessed.
Henderson’s injury might have put a slight dampener on Klopp’s evening, but it was nothing compared to the frustration of Eddie Howe, who thought his side were going to leave Anfield with a deserved point.
“I thought we got a really good performance,” he said. “In the first half we were very brave, pressed them high, tried to disrupt their rhythm, in a different way to our game against Manchester City.
“I thought we defended well for large parts, minimised their chance to play through us. I was very pleased with the commitment and unity, and bitterly disappointed with the end.”
Five minutes of added time had been indicated, but Howe said he would leave it to others to debate why eight were actually played.
“As I am sat here I have no idea,” he said. “It seemed the final whistle would never come but we needed to defend the final situation better than we did. It is a cruel game.”
Amid the frustration there was encouragement in the performance of Isak, who might have had a second goal but for a tight offside call before leaving the game with a dead leg.
“His finish and the overall performance was very good,” Howe said. “I’m really pleased with his tactical discipline.
“On the ball he gave us that pace in behind that teams need. The second goal I didn’t realise how close it is. He showed what he will bring the team.”