Such has been their capitulation that manager Antonio Conte's parting words in a furious rant about a selfish squad lacking "the fire in your eyes to win" still ring true as Spurs fell to a humiliating drubbing at St James' Park on Sunday.
Eddie Howe's Newcastle consolidated their top-four spot with the victory as they rose to third and may have simultaneously taking Spurs' place among England's elite as the London side stare at the prospect of not playing in Europe next season.
That Tottenham are still in fifth place owes much to them having played more games than Liverpool and Brighton & Hove Albion, who are both breathing down their neck with those matches in hand and a far healthier goal difference.
Cristian Stellini's sacking was inevitable as the Italian, who had never managed a top-flight team, looked out of his depth despite impressive results while playing with Conte's system when his compatriot was recovering from gallbladder surgery.
But the minute he switched tactics and Spurs deployed a back four for the first time this season, Newcastle carved them open and were 5-0 up inside 21 minutes, a shot in the arm for their own European ambitions after a 20-year absence.
That capitulation was enough to drive a host of travelling Spurs fans to the exits at St James' Park, while their team's disconsolate players looked for solutions on the pitch but could find no one to give them a lift as the home side ran riot.
"Sunday's performance against Newcastle was wholly unacceptable. It was devastating to see ... ultimately the responsibility is mine," Spurs chairman Daniel Levy said in a statement after Stellini was shown the door.
In sacking Stellini, Levy finds himself back at the point when he parted ways with Jose Mourinho exactly two years ago, but without the prospect of playing for a domestic trophy while Champions League qualification hangs in the balance.
Assistant coach Ryan Mason will take over first-team coaching duties again as Spurs search not only for a permanent manager but also a new director of football.
Italian Fabio Paratici was forced to resign as Spurs' managing director of football after his appeal against a 30-month worldwide ban over his role in transfer deals and finances while at former club Juventus was rejected.
KANE CONUNDRUM
The only bright spark on a dispiriting afternoon in Newcastle was Harry Kane's consolation goal, but Spurs fans will fear this may be his last season in the Lilywhite shirt as he nears the final 12 months of his contract.
Kane turns 30 in the close season and has yet to win a trophy at the club he has called home since he was 11.
While the striker is one goal shy of England great Wayne Rooney's tally of 208 Premier League goals to move up to second on the all-time top scorers' list, he needs 53 more to match Alan Shearer's record.
Bayern Munich have been linked with a move for Kane but he may stick around in England to try to break Shearer's record.
But whether that happens in a Tottenham shirt is the burning question with Manchester United, rejuvenated under Erik Ten Hag, also circling after Manchester City failed to prise the England captain away two years ago.
Under Levy, Spurs have built one of the most modern football stadiums which is the envy of many clubs in Europe.
But on the pitch, a lack of vision and ambition at the top has seen them fall from title contenders and Champions League finalists under Mauricio Pochettino to now be fighting for a Europa League spot.
