Stephen Kenny recorded a record-equaling eleventh European victory as a manager after his Dundalk side defeated Levadia Tallinn in Estonia tonight.
The Lilywhites entered the tie as favourites and justified their billing with a strong display - in which Dylan Connolly struck for the only goal.
Connolly fired home on 53 minutes, sliding in at the back post, after the opening period had ended scoreless.
But the signs were there that the Louth men had taken control of the match after weathering an early spell of pressure from the hosts, where keeper Gary Rogers was called into action on multiple occasions.
A doubt with a groin injury, Michael Duffy, who provided the assist for the breakthrough, was an impressive performer for Dundalk having been included from the off.
His inclusion meant Kenny made just the one change from Friday night’s league victory over St. Patrick’s Athletic, with Sean Gannon coming in for Daniel Cleary in defence.
The most clear-cut of the first half opportunities fell the way of the visitors. But prolific forward Pat Hoban was unable to control at the end of a ruthless breakaway by Robbie Benson, while Duffy and Jamie McGrath were narrowly off target.
While, in the closing minutes of the half, Benson ought to have put the Lilywhites ahead. He raced onto a loose ball in a crowded penalty area, but his powerful shot was deflected and desperately turned behind for a corner.
The pressure gauge on home goal was turned up with Kenny’s half-time words still ringing in his players’ ears and once it came, the outcome looked to be a foregone conclusion.
Yet, completely against the run of play, Rogers came to his team’s rescue, turning Pavel Marin’s deflected effort around the post.
Connolly ought to have doubled his side’s advantage when racing onto a through ball with just over a quarter-on-a-hour to play. But Estonian international Sergei Lepmets was equal to his strong shot.
Nonetheless, with the away goal in the bag, the Lilywhites will be confident of finishing the job at home in seven days' time.
Levadia: Sergei Lepmets; Markus Jurgenson, Igor Dudarev, Maksim Podholjuzin, Dmitri Kruglov; Marcellin Gando (Pavel Marin 56), Yuriy Tkachuk, Rasmus Peetson (Muamer Svraka 67), Jevgeni Harin (Mark Oliver Roosnupp 76); Roman Debelko, Nikita Andreev.
Dundalk: Gary Rogers; Sean Gannon, Brian Gartland, Sean Hoare, Dane Massey; Chris Shields, Robbie Benson; Dylan Connolly (John Mountney 88), Jamie McGrath (Krisztián Adorjan 81), Michael Duffy (Ronan Murray 90); Pat Hoban.
Referee: Bojan Nikolic (Serbia).