Arteta’s argument that Arsenal were better over the two legs against PSG is an interesting one, but I think I’ve found a statistic that might disprove that. It’s called ‘Total Goals Scored,’ or ‘TGS’ for short.
Basically, over the two legs, PSG’s TGS figure was ‘3,’ and Arsenal’s TGS was ‘1’ - one can assume from this that PSG were the better team. This conclusion is backed up by historical precedent for the team with the highest TGS winning matches.