Harry Kane's 10th league goal of the season early in the second half suggested third-placed Tottenham could mount a comeback but they huffed and puffed without much quality as Newcastle held firm to claim the three points.
Newcastle's fans celebrated noisily as Eddie Howe's side, who have lost only once in their opening 12 matches, moved into the Champions League places with 21 points.
Tottenham's best start to a top-flight season since the 1963-64 campaign has now had a harsh reality check with back-to-back defeats.
"It was a big win. We were determined to come here and be positive. Great display from us. We deserved the win," Howe
They stay third with 23 points from 12 games.