Late in the first half of the Premier League clash, proceedings were stopped after the players were alerted to a situation in the East Stand of St James' Park.
Spurs' Sergio Reguilon discussed the matter with Andre Marriner while Eric Dier spoke to fans before rushing across the pitch to call for a doctor.
Newcastle's club doctor, Paul Catterson, took a defibrillator across to the stand and, after further discussions with a steward and a police officer, referee Marriner suspended the game.
After a delay of over 20 minutes, the teams returned to the pitch, with Spurs going on to win 3-2.
It was confirmed by Newcastle that the fan had been stabilised and transferred to hospital and, later on Sunday, the club subsequently issued a further update.
#NUFC can confirm that a supporter who required emergency medical treatment during today's game at St. James’ Park is stable and responsive in hospital. 🙏— Newcastle United FC (@NUFC) October 17, 2021
A statement read: "Newcastle United can confirm that a supporter who required emergency medical treatment during the club's Premier League fixture with Tottenham Hotspur at St James' Park on Sunday is stable and responsive in hospital.
"The match was temporarily suspended during the incident, which occurred during the first half, and the supporter was awake and able to converse upon being transported to hospital.
"The club would like to thank fans for their swift actions in raising the alarm and praise those who provided immediate chest compressions, as well as thanking the on-site medical professionals who swiftly administered emergency treatment using a defibrillator located close to the incident.
"Our best wishes go to the supporter and their loved ones and we hope for a swift and full recovery."
Steve Bruce credited the fast actions of those in the crowd, while Nuno Espirito Santo praised the players and referee for their swift response.