Big-spending Tottenham crashed to a second successive Premier League defeat as Anthony Elanga and Yoane Wissa inspired Newcastle's 2-0 win on Saturday.
Roberto De Zerbi's side conceded twice in the second half in north London to extend their dismal start to the season.
Elanga put Newcastle ahead before Wissa killed off lacklustre Tottenham as their frustrated fans streamed to the exits long before the final whistle.
Newcastle manager Matthias Jaissle was able to celebrate his maiden Premier League win after a 2-2 draw against Liverpool in the German's first game following his surprise appointment as Eddie Howe's replacement.
It was another chastening result for De Zerbi, whose expensively assembled team suffered an embarrassing 3-0 defeat at Brentford in the opening game of the season last weekend.
Tottenham have spent over £300 million ($406 million) in the close-season as De Zerbi overhauled a squad that narrowly avoided relegation on the final day of last term.
But for the first time since 1992-93, Tottenham have failed to score in their first two games of a league season.
Omar Marmoush, the latest new recruit, was handed his Tottenham debut after joining on loan from Manchester City this week.
However, the Egypt forward, who struggled to make an impact with City, was unable to spark Tottenham, who were without Savio, another recent signing from City, due to a muscular injury.
A 5-1 rout of Championship side Charlton in the League Cup second round in midweek proved a false dawn for woeful Tottenham.
TONALI TAUNTS
Elanga nearly gave Newcastle the perfect start with a first-minute lob that Tottenham scrambled to safety just before it crossed the line.
That was the spark for a period of Tottenham dominance.
Mathys Tel's curler from the edge of the area was clawed away by Newcastle keeper Lukas Hornicek.
Pedro Porro and Marmoush both volleyed narrowly wide in quick succession after Newcastle failed to deal with testing corners.
Hornicek kept out Andrew Robertson's drive and Jan Paul van Hecke's header.
Tottenham midfielder Sandro Tonali was taunted by Newcastle fans in his first appearance against his former club since his £100 million move in July.
The Italian squandered a golden opportunity to silence the Newcastle jibes when he scuffed wide from close range on the stroke of halftime.
De Zerbi's side appealed in vain for a penalty after Malick Thiaw clipped Marmoush in the opening moments of the second half.
Tottenham paid for their profligacy in the 62nd minute.
After bagging his first league goal for Newcastle against Liverpool on Sunday, Elanga was back on the scoresheet, controlling Amar Dedic's cushioned header with a superb turn before unloading a lethal finish from just inside the area.
Hornicek tipped Porro's strike over the bar as Tottenham tried to vain to mount a response.
Wissa wrapped up the points for Newcastle in the 72nd minute, finishing with a clever over-the shoulder flick from close range after Nick Woltemade headed a corner towards the DR Congo forward.
Providing a fitting coda to a dispiriting afternoon for Tottenham, Tonali was hauled off with the jeers of the Toon Army ringing in his ears in the closing stages.