Two goals from Richie Towell handed Dundalk a 2-0 victory in their Europa League qualifier first leg against Jeunesse Esch of Luxembourg.
A penalty in the 59th minute set the SSE Airtricity League Premier Division table-toppers on their way after David McMIllan was fouled and Towell doubled the lead with 19 minutes remaining.
The second leg takes place on Thursday 10 July at Oriel Park.
The match started at a frantic pace and it was Dundalk who had the first chance through an overhead from McMillan, which went well over the bar. At the other end, Jeunesse had an effort cleared by Andy Boyle.
Darren Meenan then found the head of Brian Gartland, but he headed straight into the arms of goalkeeper Marc Oberweis.
McMillan shot just wide of the left-hand post when he had space following a Daryl Horgan pass and Massey then came even closer as his left-footed drive whistled past the right-hand post of Oberweis.
Boyle then headed just over the bar on the stretch from another Meenan free-kick.
Jeunesse should have taken the lead moments later when Sanel Ibrahimovic caused havoc in the Dundalk defence, and after two attempts and heroic defending from Gartland and Boyle, they survived.
Kurtis Byrne's first-time effort was shot over the bar and then Oberweis punched away a Towell free-kick.
Peter Cherrie produced a world-class save to deny a point-blank header from Kim Kintzinger after Ibrahimovic had headed back across goal. Towell closed the half with a shot straight at the goalkeeper.
The second half began with Dundalk exerting pressure and Towell once again shooting from distance, but it went well over the bar.
The Lilywhites did make the breakthrough just before the hour mark though when a Horgan cross was headed on by Byrne into the path of McMillan. He was pushed over by Eric Hoffman, who gave the referee no choice but to award the penalty.
Up stepped Towell who, despite Oberweis guessing the right way, dispatched the penalty to the bottom left corner to give Stephen Kenny's side a deserved lead.
The visitors were in full control and made it 2-0 on 71 minutes. A Ruaidhri Higgins cross was headed on by McMilan into the path of Towell and after a brilliant first touch, he settled and rifled the ball to the net.
Towell had a great chance to clinch the hat-trick when Horgan slipped him through, but he could not beat the goalkeeper in the one-on-one.
Horgan then had a shot blocked before Towell tried a speculative effort from distance, which in the end went well wide. Gartland had another great chance to make it three, but his header into the ground was off target.
The Lilywhites were in full control and despite their pressure, they did not add to their tally, but take two away goals into the return leg at Oriel Park next Thursday.
JEUNESSE ESCH: Marc Oberweis; Nenad Dragovic (Milos Todorovic 46), Ken Corral Garcia, Bryan Melisse, Kim Kintziger, Eric Hoffmann, Sanel Ibrahimovic, Alexandre Vitaly, Jonathan Ziyoko (Marko Albaneise 66) (David Solares Del Sousa 80), Adrien Portier, Martins Santols Gracia.
Substitutes not used: Denis Agoric, Amar Catic, Ricardo Alexol Delgado, Yannick Jorge (GK)
Booked: Dragovic (39),
DUNDALK: Peter Cherrie; Sean Gannon, Andy Boyle ©, Brian Gartland, Dane Massey; Chris Shields, Richie Towell; Darren Meenan, Kurtis Byrne (Ruaidhri Higgins 68), Daryl Horgan (John Mountney 84); David McMillan (Patrick Hoban 78).
Substitutes not used: John Mountney, Mark Griffin, Simon Kelly, Manuel Kaguako, Gabriel Sava (GK)
Booked: Gartland (26)