A Hale End inspired night ends with goals from Eddie Nketiah, Joe Willock and Nicolas Pepe to maintain The Gunners' 100 percent record in the Europa League.
Despite not getting in on the act with a goal, Reiss Nelson was superb on the night. The winger was a menace on both wings.
The first action of the game came from the away side. Patrick McEleney hit one from distance which caused debutant, Alex Runarsson, into a save.
The following corner was gathered by the Icelandic goalkeeper, who eased any kind of pressure.
Arsenal had half a chance on the 23rd minute. Sead Kolasinac crossed a ball into the box before Pepe headed over.
The Gunners were yet to test the goalkeeper. Nelson almost changed this moments later. The number 24 fired a right-footed effort past the post, but like the previous effort, it was off target.
Kolasinac was on the receiving end this time once he had an effort tipped over the bar from a header. WIllock worked his way to the by-line before lofting the ball into the box.
Nketiah should have made it 1-0 six minutes before half-time. A deflected effort from Pepe found it's way to the Englishman who could not react quick enough to steer goal-bound.
The number 30 made ammends for the earlier miss minutes later. Gary Rogers in the Dundalk goal failed to claim the ball, which fell to 'Eddie' who made no mistake in breaking the deadlock.
Willock made it two moments later. The midfielder fired a shot into the roof of the net to double the lead.
Arsenal were well in their stride now and they came out in good fashion after the interval.
Pepe got in on the act after a superb finish with his right-foot. The shot was high, which gave the goalkeeper no chance in saving the attempt from the far corner.
The hour mark approached and it was all Arsenal. Mikel Arteta had introduced Willian and Dani Ceballos into proceedings, the former was looking lively after his heavy involvement on the left-wing.
Ainsley Maitland-Niles tried his luck when the 70th minute struck the clock end. His effort was straight at the goalkeeper which kept it at 3-0.
Folarin Balogun was introduced for his debut with 18 minutes to play. A huge moment for the 19-year-old, he replaced Nketiah, who got his name on the scoresheet again on the night.