The Champions League made its long-awaited return this week but the Barclays Premier League teams have Everest-esque mountains to climb in the second legs if they are to progress. At the 90 minute stage in both ties, Man City and Arsenal both find themselves 2-0 down against Barcelona and Bayern Munich respectively. Optimism was rife amongst City fans before the game. With their free-flowing attacking home form they were relishing the chance to play the team Jose Mourinho labelled "the worst Barca team in years". Arsenal were quietly confident as well, after their fantastic league form this year and their new-found resilience, which was arguably born when they defeated Bayern 2-0 in the Allianz Arena in last year's Champions League. Unfortunately it was a familiar story for the English teams as they were simply outplayed and passed into submission by their opponents. Both Wenger and Pellegrini were left bemoaning refereeing decisions which they say contributed largely to their teams losses. Pellegrini's comments in particular smacked of anger and petulance in the heat of the moment. However on the face of it, it would be difficult to argue convincingly that either referee in Manchester or North London made errors. We will never know but if the results would have differed if Martin Demichelis and Wojciech Szczesny were not sent for early baths, but it would take a brave man to bet against two away wins. The two results and incidents in both games revive debates which have been given airtime in many a pub in recent years and will continue to do so over the next few. But what if anything, have we learnt from these two results? Click next to find out 5 things we now know and feel free to contribute your own in the comments section.