Newcastle gave themselves a great chance of reaching the last 16 of the Uefa Cup with a comfortable first-leg win at Belgian side Zulte-Waregem.
Dyer and Martins were influential in Belgium
Frederic Dindeleux scored the first of four second-half goals when he put Kieron Dyer's cross into his own net.
Obafemi Martins made it two from the penalty spot after Damien Duff was fouled before Karel D'Haene pulled one back with a flicked header.
Antoine Sibierski secured victory for Newcastle with a fine individual goal.
The match at Gent could hardly be described as one of European football's classic games, but there was enough action to keep the Jules Otten Stadium crowd entertained.
Waregem, the Belgian Cup winners who have endured an indifferent league campaign this season, looked lively but only caused the Newcastle defence serious problems after going 2-0 down.
Glenn Roeder's Magpies were not much better than their opponents, although all the best chances of the game fell their way.
In the first half, opportunities were few and far between, with the clearest falling to striker Martins.
The Nigerian was picked out by a driven right-wing ball from Nolberto Solano, but his shot from inside the six yards away was saved by keeper Pieter Merlier with his feet.
The pace of Martins and Dyer troubled Waregem, with the England midfielder providing a dynamic display.
Straight after the break, Dyer broke into the right-side of the penalty area and fired in a low centre that Dindeleux could only direct into his own net.
It was unfortunate for the Waregem defender, who played at Lille with Sibierski and was his the best man.
The Magpies extended their lead after Irishman Duff teased his way into the penalty area only to be felled by Merlier.
Martins lashed in his 13th of the season and that seemed to be that.
But Newcastle, who have not kept a clean sheet in 17 games, were caught napping when Loris Reina's right-wing free kick was flicked past Harper by D'Haene.
The home side had their tails up for the five minutes that followed the goal, but a cheeky individual strike from Sibierski ended stifled the Waregem revival.
After picking up a pass from Martins on the edge of the area, Sibierski nutmegged a defender before rounding Merlier to give the Magpies their third away goal and possibly a passage into the next round of the Uefa Cup.
Newcastle boss Glenn Roeder:
"I'm very pleased to come away from anywhere in Europe with a win, but I was disappointed we conceded.
"We should have done better with the free kick that led to the goal and not giving a foul away would have helped.
"It was a relatively comfortable win, but we were sloppy at times and that disappointed me."
Zulte-Waregem coach Franck Dury:
"It was never going to be easy going to Newcastle, but I accept that it's going to be even more difficult after this scoreline.
"But we're going to Newcastle to play a good game.
"When we got back to 2-1 we were playing well, but they were very dangerous when they change from defence to attack and we did not cope with that."
Zulte-Waregem: Merlier, De Brul (Van Steenbrugge 81), D'Haene, Dindeleux, Leleu, Reina, Meert (Buysse 86), Sergeant, Van Den Driessche (Vandermarliere 65), Verschuere, Matthys.
Subs Not Used: Bossut, Siani.
Booked: Leleu, Merlier, Matthys.
Goals: D'Haene 69.
Newcastle: Harper, Solano, Taylor, Bramble, Babayaro, Milner, Butt, Dyer, Duff, Martins (Luque 85), Sibierski.
Subs Not Used: Srnicek, Carroll, Edgar, Huntington, Pattison, Troisi.
Booked: Butt, Milner, Martins.
Goals: Dindeleux 47 og, Martins 59 pen, Sibierski 76.
Ref: Anton Genov (Bulgaria).