Newcastle manager Eddie Howe said his side's lack of depth was exposed as they bowed out of the Champions League group stage.
A 2-1 home defeat by AC Milan sealed the Magpies' fate after an encouraging start to their return to Europe's elite club competition after an absence of 20 years.
Newcastle had got off to a flying start as they beat Paris Saint-Germain 4-1 at home and drew 0-0 at Milan. But they took just one point from their final four games in a tough Group F as an injury crisis took its toll.
Howe said having depth is the lesson learned from a bruising campaign.
"The value of the squad, that's what exposed us," Howe said. "We haven't had the ability to utilize the squad we created, that's been a big frustration. We've gone into games with almost one hand behind our back."
Howe was forced to start the same 10 outfield players for the previous five games due to injuries and Sandro Tonali's 10-month ban for betting offenses. He made just one change to his starting lineup against Milan, but had to withdraw star performers Kieran Trippier and Anthony Gordon after the break as they tired.
Joelinton fired Newcastle into a first-half lead, but goals from Christian Pulisic and Samuel Chukwueze condemned Howe's men to a third consecutive defeat.
"We've got a very stretched squad, those players have gone again and again and I couldn't be prouder," said Howe. "We've left it all out on the pitch. I don't think we have any regrets, but we will learn from it."
Goalkeeper Martin Dubravka fails to keep out a shot from Samuel Chukwueze, condemning Newcastle to a 2-1 defeat at St James' Park. REUTERS