Linfield saw off Montenegrin side Sutjeska to reach the play-off round of the Europa League.
Linfield had won the first leg 2-1 thanks to Kirk Millar's brace, and they quickly opened the scoring at Windsor Park through Mark Stafford.
Bojan Bozovic equalised on the night, and did so again after Shayne Lavery had restored the Northern Irish side's lead, but Matthew Clarke had the final say as Linfield won 3-2 on the night and 5-3 on aggregate.
Dundalk's adventure was ended by Slovan Bratislava, as first-half goals from Rafael Ratao and Aleksandar Cavric added to David Holman's first-leg strike to put the Slovakians 3-0 up on aggregate.
Michael Duffy pulled one back but that was as far as the comeback went, and Erik Daniel scored in stoppage time to round off a 4-1 aggregate win for Slovan.
Danel Sinani scored as Luxembourg side Dudelange won 1-0 away to Nomme Kalju to complete a 4-1 aggregate success.