Eric Dier headed us into a first half lead, but Aleksandar Mitrovic's close-range equaliser with 16 minutes left brought the Magpies right back into the contest.
And it was the visitors who scooped maximum points when Ayoze Perez squeezed the ball past Hugo Lloris in the 93rd minute, condemning us to only our second league defeat of the season - and our first since the opening day.
Spurs (4-2-3-1): Lloris, Walker, Alderweireld, Vertonghen, Rose, Dier, Carroll (Son 69), Lamela (Chadli 86), Alli, Eriksen, Kane. Substitutes (not used): Vorm, Trippier, Davies, Bentaleb, Onomah.
Newcastle (4-4-2): Elliot, Dummett, Mbemba, Coloccini, Janmaat, Wijnaldum, Colback, Anita (Gouffran 90), Sissoko, Cisse (Mitrovic 72), De Jong (Perez 63). Substitutes (not used): Darlow, Thauvin, Sterry, Mbabu.
Goals: Spurs – Dier 39; Newcastle – Mitrovic 74, Perez 90+3.
Yellow cards: Spurs – Carroll, Rose; Newcastle – Colback, Perez.
Referee: Roger East.