London - Tottenham had only themselves to blame for a shock 1-0 home defeat to Newcastle, according to manager Mauricio Pochettino, who refused to hide behind being denied a late penalty on Sunday.
Joelinton's first goal for the Magpies gave Steve Bruce's men a first-half lead to defend and they did so manfully to pick up their first points of the season.
"It's easy (to analyse), we didn't play well. I'm very disappointed about our performance and our result," said Pochettino.
"Again we concede a very cheap goal in the first-half and then it was difficult.
"We weren't capable to break down their organisation. We created some chances but not enough. We cannot justify our performance. We needed more desire, more aggression with the ball."
Spurs were saved by VAR to claim a fortunate 2-2 draw away to Manchester City last weekend as the champions had a late goal ruled out, just as they did in a dramatic Champions League quarter-final between the pair last season.
However, it was Tottenham's turn to feel aggrieved as Harry Kane was felled by Jamaal Lascelles inside the area, but VAR did not overturn Mike Dean's initial decision to wave play on.
Newcastle had suffered a terrible start to the season with defeats by Arsenal and Norwich, the latter of which forced Bruce to cancel a day off for his players for extra training.
That work clearly paid off as a disciplined and dogged Newcastle frustrated a Spurs side lacking in invention without Christian Eriksen - who was again left on the bench with his future at the club in question.
"All week we've worked on the system. Tactically to go and nail it the way we did on one of the big platforms in Europe now is outstanding."
Newcastle fans continued to voice their displeasure with Mike Ashley's ownership of the club for a lack of investment that contributed to Rafael Benitez not extending his contract to remain in charge this season.
But there was finally some reward for the club-record Pound 40 million splashed on Joelinton as the Brazilian striker pounced on some awful defending from Davinson Sanchez to fire Newcastle in front on 27 minutes.
"Whoever followed Rafa it was going to be a rocky ride," added Bruce, who was far from a popular choice as the Spaniard's successor.
"The supporters can only witness the team today."
Spurs continued to probe without much cutting edge and Eriksen was eventually called for, along with Giovani Lo Celso for his home debut just after the hour mark.
Eriksen's contract expires at the end of the season, meaning Tottenham will have to sell him before the transfer window closes across Europe on September 2 or run the risk he leaves the club for free next summer.
And not for the first time this season, Pochettino hinted the cloud hanging over the Dane's future has affected his squad .
"You need not only quality players but to create a very strong team dynamic and bonding. At the moment that is very far from what we expect."
Just like on the opening day of the season when Eriksen helped overturn a surprise 1-0 deficit against Aston Villa, his introduction sparked Spurs into life.
Kane should have had a chance to level from the spot when he was wiped out by Lascelles as the defender stumbled in the box.
Referee Dean turned down the appeals and the decision was not overturned after a VAR review as it was deemed not a "clear and obvious error".
However, the Premier League's high bar to not overturn referees' original decisions will be scrutinised as it seemed a certain penalty.
Moments later, Lucas Moura spurned the hosts' best opening of the game by firing over Moussa Sissoko's low cross and Newcastle saw off a bombardment during six minutes of stoppage time for a vital victory.