It would seem Arsenal cannot mirror their premier league achievements in the champions league when they visited Croatia.
Dinamo Zagreb who have not won a group stage match for the last 16 years opened the scoring via an own goal, Pivaric’s shot hitting Oxlade-Chamberlain before finding the net.
A second bookable offence saw Giroud handed a red in the closing minutes of the first half, adding to Arsenal’s woes.
It got worse for Arsenal in the second half, when before the hour Fernandes sent a header past Ospina.
Arsenal tried to mount a comeback, but Walcott’s goal was moot as Dinamo Zagreb extend their unbeaten run to 42 games in all competitions.