Twenty-one minutes to seal abject ignominy for Tottenham Hotspur, 21 minutes to signal the failure of their season. Twenty-one minutes to bring jubilation for Newcastle United, 21 minutes to propel their charge towards a Champions League place that Spurs had designs on.

A startling start brought Newcastle’s best day under Eddie Howe, their finest for many a year. A surreal scoreline in the first quarter – with Newcastle five goals ahead – meant that, in a season laced with low points for Tottenham – Leicester, Sheffield United, AC Milan, Bournemouth, many of Antonio Conte’s press conferences – this was a new nadir.

It was perhaps their most embarrassing match since they lost to a Dinamo Zagreb team whose manager was in jail. Spurs could count themselves fortunate the final scoreline was only 6-1. It was shameful nevertheless.

For Cristian Stellini, it was unwanted proof that he really shouldn’t be his own man. Conte’s long-time sidekick had seemed Conte-lite, a Conte copycat. As he finally deviated from his mentor’s blueprint and picked a back four, Tottenham were picked apart with embarrassing ease. As Stellini went rogue, it went horribly wrong. Gameplans can fail, but rarely as quickly, as comprehensively, as crushingly. It may be the last time Stellini is allowed to think for himself.

Because, some 455 days and 63 games since Tottenham began with a match with just two centre-backs, they conceded four in 19 minutes, changed shape and let in another after two minutes more. Booed off by supporters after a 23-minute cameo last week, Davinson Sanchez was summoned after 23 this time, sent on to be a third centre-back. Conte’s system was back but this lifeless, lacklustre group, devoid of belief and demoralised, form part of his legacy.

There were three points between Spurs and Newcastle at kick-off; they were separated by three goals after nine minutes. By then, the game was over, a 600-mile round trip a wasted journey in a wasted season for Tottenham fans.

Their side conceded after one minute and one second; they were five adrift after 21 minutes. It was the second-quickest 5-0 lead in Premier League history. This could have been a play-off for a Champions League spot. Instead, such is the scale of Spurs’ meltdown, they may not even qualify for the Europa Conference League.

This wasn’t a defeat as much as a debacle, a disaster. Dispirited, disorganised, dismal ... Tottenham were shambolic. Their offside trap was breached for the second and fourth goals. Newcastle passed the ball through them for the fifth. Spurs stood off Joelinton for the first. They lost the ball in their own half for the third. It was as though they had a checklist of failings and ticked them all off.

There were different forms of humiliation. Harry Kane scored the least consoling of consolation goals; a grim-faced reaction instead of a celebration showed what he thought. Hugo Lloris went off at half-time, perhaps with backache after retrieving the ball from the back of his net five times.

A few months ago, he was conceding twice to Lionel Messi in a World Cup final. Now he let in two in nine minutes to Jacob Murphy, who had one goal in his previous 70 appearances. Alexander Isak added a still quicker double, with two in three minutes.

Among a host of terrible performances at the back for Spurs, Pedro Porro, Conte’s last signing, produced perhaps the worst: he allowed Joelinton too much room for the first goal, appealed in vain when the Brazilian ran away from him for the second, reacted too slowly when the substitute Callum Wilson stole in for the sixth.

And while Tottenham were shocking, Newcastle were stunning. They were clinical in front of goal, but long passes, particularly Joe Willock’s outside-of-the-boot ball for Isak’s first goal, were brilliantly executed. They had the energy and the desire Tottenham clearly lacked.

While Stellini’s decision-marking was sadly flawed, Howe’s was excellent. Joelinton had lined up in midfield in defeat to Aston Villa. Restored to the forward line, he had a goal and an assist after six minutes. With barely a minute on the clock, he drove forward, cut inside and shot, Lloris parried and Murphy tapped in. Then the Brazilian timed his run to meet Kieran Trippier’s diagonal pass, rounded Lloris and slotted in the second.

Tottenham showed different forms of generosity. Eric Dier tried to find Heung-Min Son, Fabian Schar intercepted and Murphy, long a stranger to the scoresheet, curled in a shot from 25 yards. After Willock’s majestic pass, Isak was sent scurrying clear and he beat Lloris.

Then, with no hint of a challenge, Newcastle constructed a fine passing move that culminated in a cutback from Sean Longstaff for Isak to drive in his second. Wilson added a sixth, barely a minute after coming on. Ivan Perisic cleared off his own line to deny Anthony Gordon a seventh. But by that stage, it had already been mortifying for Tottenham and Stellini for an hour.