As defender Martin Bjornbak got back to clear off the line to deny Eddie Nketiah, Molde had an early escape.
When they came from behind to beat Molde to make it three wins out of three in Group B, Arsenal was glad for two own goals.
Although Kristoffer Haugen redirected into his own net as Nketiah squared for Joe Willock, Arsenal drew level on the verge of half-time.
When Martin Ellingsen left keeper Bernd Leno pounding the ground in frustration after the keeper was beaten from distance after 22 minutes, the Norwegians then shocked the hosts.
After 69 minutes, Nicolas Pepe made it 3-1 from Bukayo Saka’s help and Willock scored a fourth goal late on.
Before Sheriff Sinyan conceded another own goal from Willock’s cross just after the hour, Sead Kolasinac somehow shot over with the goal at his mercy.
Rapid and Dundalk played a great game, which ended 4-3.
Ljubičić (22), Arase (79), Hofmann (87) and Demir (90) scored for Rapid, and Hoban (7), McMillan (81-11m) and D. McMillan (90 + 6-11m) scored for the guests.
Group B:
Arsenal 4 – 1 Molde
Rapid 4 – 3 Dundalk
Arsenal 4 – 1 Molde
Goals: 0-1 Ellingsen 21, 1-1 Haugen OG 45, 2-1 Sinyan OG 62, 3-1 Pepe 69, 4-1 Willock 88
Bookings: Luiz, Saka
Arsenal: Leno, Kolasinac, Luiz, Mustafi, Maitland-Niles, Ceballos, Xhaka, Pepe, Willock, Willian, Nketiah
Substitutions: Cedric, Saka, Tierney, Elneny
Molde Linde, Wingo, Bjombak, Gregersen, Haugen, Aursnes, Hussain, Ellingsen, Eikrem, Bolly, Ohi
Substitutions: Sinyan, Erling, Ola, Mattias, Leke
Rapid 4 – 3 Dundalk
Goals 0-1 Hoban 7, 1-1 Ljubicic 22, 2-1 Arase 79, 2-2 McMillan 82, 3-2 Hofmann 87, 4-2 Demir 90, 4-3 McMillan 90+6
Bookings: Hofmann, Stojkovic, Hoare, Cleary, Sonnleitner, Shick, Dummigan, Keegan
Rapid: Paul, Ulliman, Barac, Hofmann, Stojkovic, Petrovic, Ljubicic, Arase, Christoph, Shick, Kara
Substitutions: Sonnleitner, Grahovac
Dundalk: McCarey, Hoare, Cleary, Boyle, Leahy, Shields, Hannon, Flores, Sloggett, Duffy, Hoban
Substitutions: Dummigan, Mountney
