How does it work?Thirty-six sides entered into the new "league phase" and now just four remain with a month-and-a-half to go in the UCL campaign.Barcelona, Paris Saint-Germain, Arsenal, and Inter Milan are through to the semifinals,

Paris Saint-Germain hold a slender advantage as they welcome Arsenal for the climax of the UEFA Champions League semi-finals.

Felix Zwayer has been appointed as the referee for Arsenal 's Champions League semi-final second-leg decider against Paris Saint-Germain on Wednesday night. UEFA have announced that the German official, 43, will take charge of the return leg in Paris, with Arsenal a goal down on aggregate following last week’s narrow defeat at the Emirates Stadium.