Alexander Isak scored the winner as a largely second-string Newcastle came to life after the break to beat a much-changed Manchester City and reach the fourth round of the Carabao Cup.
Newcastle, who lost to Manchester United in last year's final, made 10 changes from Sunday's 8-0 win at Sheffield United and barely got a kick in a first half dominated by the visitors.
But with Bruno Guimaraes and Anthony Gordon sent on at the break, the Magpies were transformed, with Isak slotting home following fine work from Joelinton.
Disciplined but passive in the face of City's possessional dominance, Eddie Howe's men were fortunate to still be level after 45 minutes, with Julian Alvarez missing two decent chances.