Ethan Nwaneri produced a moment of brilliance to secure Arsenal’s place in the top eight and ensure Mikel Arteta can take his team on a warm-weather camp next month.
Having embarked on a relentless run of form after a break in the UAE last January, Arteta will be hoping another spell in the sun can similarly rejuvenate his team. And with 10 days off from February 5, the exhausted Gunners shall be glad of some respite.
This was harder work than expected as former Bournemouth player Arnaut Danjuma put Girona ahead before Jorginho levelled from the spot.
Then Nwaneri, 17, became the second youngest Englishman to score in the Champions League – bettered only by Jude Bellingham – by dispatching a ferocious attempt from the edge of the box.
Arteta had changed seven of the team that started away to Wolves but it was still a side packed with experience, Nwaneri aside.
And having waited five months, loanee Neto became Arsenal’s oldest debutant for 110 years – aged 35 years and 194 days.
But this was an anxious outing for the goalkeeper who will only play again if David Raya remains out injured.
He went walkabout for Danjuma’s goal having been close to gifting Girona, who were already out of contention, an opener two minutes in with a nightmare first touch that was almost charged down by Yaser Asprilla.
Arsenal did begin to dominate after that shaky start and Riccardo Calafiori was ruled marginally offside following a neat finish.
A series of corners predictably caused havoc but they were still waiting for a first shot on target when Danjuma got behind Thomas Partey down the left, spotted Neto 25 yards off his line and curled it around the goalkeeper, who still tried to save despite being behind well outside his box.
Danjuma had another effort blocked before Arsenal found a new gear and flipped the scoreline in four minutes.
Partey may have been caught napping for the opener but he displayed plenty of determination before being tripped by Arnau Martinez to earn the clear penalty that Jorginho calmly rolled home.
Neto made a solid enough save from Oriol Romeu before Nwaneri delivered his stunner. He received possession from Trossard on the right of the penalty area and shifted centrally to find a better angle to fire home.
Leandro Trossard rattled the bar and Jurrien Timber appeared to accidentally stop a corner from being deflected in for 3-1.
But much of the second period passed by uneventfully. Raheem Sterling was furious to be booked for a dive and Christian Stuani thought he had equalised only for Portu to be flagged narrowly off in the build up. Sterling then had another penalty saved deep in added time as Arsenal secured third spot.