Arsenal claimed a 3-0 victory over a stubborn Dundalk at the Emirates on Thursday.
And Nketiah re-paid the faith by pouncing on a loose ball in the box to net Arsenal's opening goal after 42 minutes.
Only moments later, the Gunners were two goals ahead thanks to the excellent Joe Willock, who finished superbly past Gary Rogers.
Nicolas Pepe then made it 3-0 just a minute after half-time with an incredible 18-yard strike that sailed into the top corner.
Arteta's side are now top of Group B after two wins from their opening two Europa League matches.
Watch Pepe's spectacular goal below:
When Pepe hits his full potential he is gonna be unplayable! It's a mad goal!pic.twitter.com/41lucDttGg
— Wolf (@WoolwichCannons) October 29, 2020