Titus Bramble scored as Newcastle took control of their Uefa Cup second qualifying round tie with a first-leg win at Latvian side FK Ventspils.
Duff (right) caused problems for Ventspils with his direct running
Bramble climbed above the Ventspils defence to head home Emre's corner 20 minutes from time.
An Emre shot almost deflected into the Ventspils net, while Damien Duff, Shola Ameobi and Scott Parker went close.
Ventspils had several chances of their own, with Shay Given making a brilliant save to deny Igors Slesarcuks.
The Latvian team had taken just five minutes to expose Newcastle's defensive frailties, Given's one-handed stop coming after Slesarcuks ghosted past Bramble.
Given was in action again shortly afterwards, cutting out a dangerous cross from Deimantas Bicka, while Vladimirs Kolesnicenko headed just wide with 17 minutes gone and Sergey Zangareev threatened with a free-kick.
But Newcastle, who enjoyed the majority of the possession, crafted a series of openings of their own.
A shot from Emre struck defender Jean-Paul Ndjoumeck-Ndeki and forced a decent save from Andris Vanins.
Ameobi headed a cross from Nolberto Solano over the crossbar and, with 27 minutes gone, failed to apply the crucial touch to Duff's pass across the face of goal.
Shortly afterwards, Solano played Ameobi through on goal but his strike was blocked.
Ventspils took the game to Newcastle after the break, with Kaspars Gorkss narrowly missing with a strike from the edge of the Newcastle box.
Andreys Butriks almost converted a cross from Zangareev and was later through on goal but wasted the chance with a heavy first touch.
Summer signing Duff was at the heart of many of Newcastle's attacks. The Irishman's pass created a shooting chance for Parker but the midfielder could not keep his effort on target.
Duff came close to scoring himself, shooting just wide after cutting in from the left.
But it was Bramble who scored the decisive goal, powerfully heading Newcastle in front with 20 minutes left.
FK Ventspils: Vanins, Ndjoumek-Ndeki, Kaspars Gorkss, Kacanovs, Bicka, Zangareeb, Dubensky (Kosmacovs 90), Vukovic, Kolefnicenko (Pokarynin 84), Butriks, Slesarchuk (Zizilevs 16).
Subs Not Used: Davidovs, Sokolskis, Soleicuks, Stukalinas.
Newcastle: Given, Carr, Moore, Bramble, Babayaro (Ramage 87), Solano (Milner 84), Emre (N'Zogbia 80), Duff, Parker, Butt, Ameobi.
Subs Not Used: Harper, Luque, Taylor, O'Brien.
Booked: Moore, Butt.
Goals: Bramble 70.
Ref: Stephane Lannoy (France).