id play a defensive 4-3-2-1
bellerin - kos - chambers - monreal
ramsey - coq - elneny
welbeck - ozil
giroud
you need 3 central midfielders to form a line in front of the back 4. i would keep mert out of this match. they will pose no aerial threat. i would prefer chambers (or gabriel)
ramsey - coq - neny across the middle should provide workrate and industry and hopefully can cut off service to their front 3. welbeck/giroud are incredibly hard working and will track back to help defend. and ozil is capable of providing the one key ball we need.
sit back. keep a clean sheet at home. maybe grab a late one ourselves. the away leg is going to be incredibly difficult, if we keep a home clean sheet then at least we dont have to worry about the away goal rule