Sir Bobby Robson last night promised to "battle to the wire" in pursuit of a Champions League spot after events conspired against his Newcastle side at White Hart Lane.
Andy O'Brien's last-gasp own goal condemned the Magpies to their first Premiership defeat of 2004 despite dominating a game of maximum effort but minimal chances.
The defeat marked the fourth away game in a row where Newcastle had conceded a crucial goal in the dying minutes but, as if that was not bad enough, Robson was left to rue more than the dropped points.
The United boss was furious that referee Howard Webb had waved away his side's appeals for a first-half penalty, despite Spurs full-back Mauricio Taricco appearing to clearly impede Aaron Hughes as he surged into the opposition penalty area.
And Robson was left with injury worries ahead of next weekend's crucial St James' Park showdown with Charlton after centre-half Titus Bramble was kept on the sidelines with a knee problem and striker Craig Bellamy complained of a muscle twinge at the final whistle.
"I'm bitterly disappointed to lose the game," said Robson. "We certainly didn't deserve to lose it. We were the better side overall and it's a blow to come away with nothing.
"The penalty was a nonsense. It was clear-cut, a stonewall decision. I told the referee what I thought about it at half-time.
"I told him that I wanted that penalty and I wanted him to have the courage to give it."
Newcastle enjoyed plenty of possession against a Spurs side now just five points behind them in the Premiership table, but they were unable to break down an obdurate opposition defence.
Kasey Keller saved well from Olivier Bernard before the break but, after that, Newcastle were restricted to playing most of their football in front of the opposition backline.
Their inability to carve out clear chances ultimately cost them, but Robson was left more disappointed by the manner of Tottenham's late winner.
The otherwise impressive Jonathan Woodgate failed to clear his lines and, after substitute Stephane Dalmat had crossed from the right, O'Brien diverted the ball into his own net.
"It was cruel luck on us right at the end," said Robson. "We lost the ball stupidly from a throw-in and that cost us.
"It's happened before this season at places like Portsmouth and Birmingham, but I don't think you can fault the players for the effort and energy they put in.
"It was harsh on the back four because I think they played very well right the way through."
Newcastle will need to pick themselves up quickly as Saturday's home game with Charlton could prove crucial in the battle to claim fourth spot.
The Addicks' 1-0 win over Middlesbrough on Saturday lifted them back into the driving seat, but Robson expects plenty more twists and turns before the end of the campaign.
"It's always been a dogfight," he said. "We play Charlton next and that's a bit of a cliffhanger now. But there's something like eight teams going for fourth place and it will be nip and tuck for the rest of the season.
"Our experience will help us because we've been there before and we know what it takes. But it's the players that are the most important thing and, even though we lost, I think you could see the confidence in the side."
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