Arsenal were kept at bay for 42 minutes by Dundalk before ultimately easing to a comfortable Europa League victory.
Arsenal made it two wins from two in this season's Europa League group stage as they beat Dundalk 3-0 at Emirates Stadium.
Mikel Arteta made 10 changes to the side that lost 1-0 at home to Leicester City last weekend and they were kept at bay for 42 minutes by an effective Dundalk rearguard until Eddie Nketiah pounced on a goalkeeping error.
Joe Willock doubled the lead before half-time and Nicolas Pepe's super strike put the Gunners firmly in control, allowing them to ease through the closing stages with one eye on the weekend trip to Manchester United.
Patrick McEleney tested Alex Runarsson with the first effort of the match as Dundalk showed they were prepared to work the ball forward rather than simply clear their lines.
Arsenal unsurprisingly controlled possession yet found it difficult to pick their way through a packed visiting defence, but Nketiah got the breakthrough three minutes before half-time, turning home from point-blank range after goalkeeper Gary Rogers made a mess of an attempted punch.
Dundalk were punished further barely 90 seconds later, Willock firing high into the net after Nketiah and Pepe led a swift break in the visitors' half.
Any faint thoughts of a comeback were quashed just a minute after the restart, Pepe taking a clever touch and curling a fine effort into the top-right corner from the edge of the Dundalk box.
Nketiah just failed to prod a cross beyond Rogers from Cedric Soares' cross, and the lively Reiss Nelson teed up Kieran Tierney to blast over, but the fight was gone from the Irish champions.
Nicolas Pépé has been directly involved in six goals for Arsenal in the Europa League (eight appearances), with all of his goals coming at the Emirates (three) and all of his assists coming away from home (three).
Tottenham Lose: Alli and Bale hooked as sloppy Spurs suffer setback
Dele Alli and Gareth Bale failed to make the most of Tottenham starts as they were substituted in a dismal defeat at Royal Antwerp.
Jose Mourinho's big-name substitutes failed to save Tottenham from a 1-0 Europa League defeat at Royal Antwerp on Thursday.
Dele Alli and Gareth Bale both came into the Spurs side but neither lasted an hour, the former withdrawn among four half-time changes as Mourinho's men trailed to Lior Refaelov's 29th-minute strike.
The visiting coach turned first to Son Heung-min and then to Harry Kane - replacing Bale 13 minutes later - yet the in-form pair could not come up with a leveller despite a slightly improved second-half showing.
Again the pre-match optimism prompted by beating Burnley on Monday dissipated, with Tottenham too often this season following big victories with inexplicable setbacks.
While Spurs toiled from the outset, the Belgian Pro League leaders seized the biggest opportunity of the first half as Dieumerci Mbokani ripped the ball away from Ben Davies, raced towards goal and squared for Refaelov to control and lash into the net.
Despite the raft of Mourinho changes, Antwerp twice could have increased their advantage early in the second half.
More slack play - this time from Harry Winks - let Refaelov in, prompting a sublime recovery tackle from Davinson Sanchez, before Mbokani somehow missed the target when found by Koji Miyoshi with the goal at his mercy.
Pressure increased on the Antwerp goal, but they were soon in again on the counter, only for Simen Juklerod to fire high into the stands with only Hugo Lloris to beat.
Although that miss kept Tottenham in the match, they could not create a presentable opportunity for Son or Kane as Mourinho lost for the first time in 16 Europa League matches - including qualifiers.
(Goal)
