Newcastle established a comfortable first-leg lead over Slovakian side ZTS Dubnica in the Intertoto Cup after scoring twice in the first 10 minutes.
Chopra was making only his second start for Newcastle
Striker Michael Chopra claimed his first goal for Newcastle, slipping the ball past Dusan Pernis on four minutes.
Alan Shearer got the second three minutes later, forcing the ball in after Charles N'Zogbia's cross.
Just before the interval Igor Drzik headed home, but James Milner's clever lob restored Newcastle's two-goal lead.
The scoreline flattered Newcastle, who for long periods were outplayed by Dubnica in stifling hot conditions.
But the Slovakian side were undone by their inability to contain Milner, who pushed forward to support Shearer in attack in the second half.
Just before his goal Milner superbly weaved his way past a succession of Dubnica defenders only to hit the post with his final shot.
Milner was heavily involved in Newcastle's opening goal, his astute pass releasing Chopra, who calmly slotted home.
Soon after Newcastle doubled their advantage with Shearer on hand to prod home at the far post.
Having established almost total control of the game Newcastle relaxed, allowing Dubnica to dominate in midfield.
First Marian Adam hit the post after rounding Steve Harper, while the Newcastle goalkeeper made a superb triple save, twice denying Drzik and then foiling Peter Kiska.
Just before the interval Dubnica got a deserved goal, Tesak powering a header past Harper after Drzik swung in a cross from the right.
Newcastle play the second leg at St James' Park next Saturday.
If they get past Dubnica, they are likely to face Deportivo la Coruna in the semi-finals, with Lazio and Marseille potential final opponents.
Newcastle boss Graeme Souness told the Newcastle website:
"I was a little nervous coming into the game.
"It was always going to be a possible banana skin because they've already played four competitive matches this season and we have only been back in training for a fortnight.
"It was always going to be tricky, but I cannot emphasise enough how important fitness is in these games."
ZTS Dubnica: Pernis, Pleva, Drzik, Novak, Kopacka, Kiska, Svestka, Izvolt, Zimen, Tesak, Adam.
Subs: Postrk, Svikruha, Grendel, Brusko, Filo, Skultety, Augustini.
Newcastle: Harper, Taylor, Babayaro, Faye, Elliott, Boumsong, Milner, Butt, N'Zogbia, Chopra, Shearer.
Subs: Given, Ramage, Brittain, Huntington.
Referee: Alon Yefet (Israel)