Maritimo substitute Fidelis ruined Newcastle's night as they limped rather than marched into the knockout stages of the Europa League after a 1-1 draw.
The striker, who might even have snatched victory deep into stoppage time, came off the bench to level for his side with a powerful shot on 79 minutes.
He cancelled out Sylvain Marveaux's first Magpies goal 11 minutes from time and allow Bordeaux to climb to the top of Group D by virtue of their 2-1 victory over Club Brugge in Belgium.
Alan Pardew's men will now have to win in France on December 6 if they are to snatch back top spot in a game which will be a dead rubber in terms of qualification, but upon which much could rest as the Champions League drop-outs prepare to enter the competition in the new year.
A draw was little more than the visitors deserved on a night when Newcastle once again played in fits and starts in front of a meagre crowd of 21,632.
However, the result was not the only disappointment for Pardew, who saw the in-form Hatem Ben Arfa limp off with a hamstring injury and striker Papiss Cisse follow him down the tunnel shortly after half-time.
Newcastle ran out having lost their last two games at St James' Park - to West Ham and Swansea in the Barclays Premier League - and knowing a third defeat was simply unthinkable if they were to extend their stay in Europe.
But once again, they were less than fluent in the early stages as Maritimo made light of their billing as the group's whipping boys to take the game to their hosts.
The Magpies mustered the first attempt on goal when left-back Davide Santon cut inside to unleash a fierce third-minute shot which keeper Romain Salin managed to repel with some difficulty.
However, with Sami and Danilo Dias causing problems on both flanks, it was the Portuguese outfit who settled better.
Striker Adilson might have done significantly better with six minutes played when he seemed certain to meet a left-wing corner unopposed in front of goal, but somehow contrived to allow the ball to sail over his head.
Tim Krul then had to deal with a long-range effort from Ruben Ferreira which skidded nastily off the turf in front of him.
Pardew had named a strong side despite the absence of the suspended Cheick Tiote and the injured Jonas Gutierrez and Shola Ameobi, and that meant a first involvement in the competition for Ben Arfa.
The Frenchman has been one of the few men to emerge with any credit in recent weeks with his team misfiring alarmingly, and although he endured a quiet start to the game having been asked to play in the hole behind lone striker Cisse, he gradually warmed to his task.
He had already tested the mettle of the Maritimo defence with a couple of fleet-footed runs when he collected Gael Bigirimana's 23rd-minute pass and fed it perfectly into the run of compatriot Marveaux.
The winger accelerated away from full-back Ferreira before sliding a left-foot shot through Salin's leg to open his Newcastle account and edge them closer to the knockout stages.
Cisse thought he had made it 2-0 eight minutes before the break when he pounced after Salin had only been able to parry Bigirimana's long-range effort, but his strike was harshly ruled out by an offside flag, and there was worse to come for the home side.
Ben Arfa had gone down heavily under David Simao's challenge during the build-up and, after treatment, limped off the pitch clutching his hamstring.
Demba Ba, a man Pardew would have preferred to leave on the bench for emergencies, joined the fray as his replacement, but there were mixed emotions for the Magpies as they headed for the dressing room at the break.
Cisse's involvement ended within five minutes of the restart when he walked gingerly from the pitch to be replaced by midfielder Romain Amalfitano.
Sammy Ameobi's deflected 52nd-minute effort prompted another less-than-convincing save by Salin, but Krul had to tip Danilo's speculative strike over two minutes later with Maritimo still in the game.
They went close to a 59th-minute equaliser when Sami met Danilo's cross with a firm header, but could not hit the target, and the provider on that occasion curled a low effort just wide three minutes later.
Ameobi might have extended the home side's lead with 21 minutes remaining when he reacted first to Steven Taylor's flick-on, but he stabbed his effort just wide.
Krul had to beat away Ferreira's 73rd-minute drive, but there was little he could do to deny the powerful Fidelis as he burst past first Taylor and then Fabricio Coloccini to blast home an equaliser.
Fidelis volleyed across the face of goal from substitute Ruben Brigido's cross in the third minute of stoppage time, and the final whistle was greeted by boos from the home fans.