Despite both teams having virtually nothing to play for other than pride, the first half was very eventful. The opening chance fell to the visitors inside just four minutes, as Raheem Sterling turned nicely before firing just wide of the far post.
Leandro Trossard missed a glorious opportunity moments later, as he failed to connect properly right in front of goal, with the ball bouncing wide.
The Gunners did have the ball in the net on 12 minutes, but Riccardo Calafiori was denied a second goal in as many games by the offside flag after a lovely finish at an acute angle. Girona started to grow into the half, and took a shock lead through former Tottenham player Arnaut Danjuma just before the half-hour mark.
After running in behind, he shot first-time past Neto, who after a shaky start was caught well out of his goal on his Arsenal debut.
Mikel Arteta’s men recovered well though, and 10 minutes later were awarded a penalty after Thomas Partey was brought down in the box. Jorginho produced his trademark run-up before slotting coolly past Pau Lopez to level proceedings.
The Gunners then turned the score around before the break, as Ethan Nwaneri cut inside before brilliantly striking into the bottom corner for his first UCL goal, and Trossard almost made it three in quick succession as he struck the underside of the crossbar from a tight angle.
Arsenal took their momentum into the second half and almost had a third straight away. Alejandro Frances almost sliced into his own net and was grateful to see the ball loop just wide, and from the resulting corner, Nwaneri’s ball was only stopped from going straight in from his own teammate Jurrien Timber, coming on as a half-time substitute for Partey.
The 17-year-old was gliding across the pitch and almost secured a brace with a half-volley that flashed inches wide.
The Gunners were dominant but were almost hit with a sucker punch when two Girona substitutes combined with what they thought was an equaliser. Portu fed a lovely ball to the back post to Christhian Stuani who slid home, but the goal was disallowed for offside.
Arsenal won another penalty in stoppage time when Frances handled Sterling’s attempted pass, but the Chelsea loanee saw his effort saved off the spot.
They still held on for victory though, which extends their impressive unbeaten away run over all competitions to nine games, while the hosts exit Europe on a low.