Real Betis took the lead earlier in the second half thanks to a goal from Igelsias and then Juanmi.
Igelsias found himself ahead of Starfelt and was able to sneak a shot into the net, making it 3-2. You could probably say Soro should have closed the space and attempted to stop the cross but the central midfielder was attempting to cover for Anthony Ralston, who had tried to spark an attack moments before.
A set piece was then failed to be cleared and then Juanmi managed to find the corner with a shot that kissed the post. David Turnbull should have done better but it was a composed finish that Joe Hart had no chance with given the amount of bodies in the way.
Celtic will be rueing the missed opportunity at 2-0 when Jota was 1v1 and Claudio Bravo pulled off an impressive stop. Fine margins in Europe and now Celtic have a mountain to climb to get back in this game.