Arsenal took a 1-0 lead at the break thanks to an Aubameyang goal that came just as Arsenal seemed to be fading.
They started excellently and should have gone ahead in the 16th minute when Martinelli saw an effort saved then another cleared off the line in quick succession.
The Gunners did lose some of their composure when Luiz went off with an injury after 31 minutes, but – as he so often does – Aubameyang popped up with a vital goal in stoppage time.
But Frankfurt equalised 55 minutes on the clock through Daichi Kamada with his first European goal.
9 minutes later, Frankfurt took the lead and its Kamada with a brace. All from a poorly defended corner – the ball drops to Kamada in space at the edge of the box and he tucks a low shot into the bottom-left corner.
The win means Frankfurt are now second in the group with the ball in their court in terms of qualification for the knockouts after Standard Liege and Vitoria drew.
As for Arsenal, they’re still almost certain to qualify, but they’ll have to wait for the final match to secure their spot.