Theo Walcott's late goal was not enough to prevent 10-man Arsenal losing 2-1 to Dinamo Zagreb in their first Champions League Group F match at Stadion Maksimir.

Arsenal took the game to the hosts immediately and were denied an early opener only by a superb save from home goalkeeper Eduardo, who somehow managed to keep Olivier Giroud from heading home Santi Cazorla's corner.

Marko Pjaca gave the Gunners a warning sign just two minutes later when he fired wide as Dinamo looked to counter, but the visitors should have led when Eduardo produced an even better stop to keep out Giroud's rebound after the striker had headed Alex Oxlade-Chamberlain's cross against the post.

All of Arsenal's early dominance was in vain, however, when the Croatian champions took the lead midway through the first half thanks to an unfortunate Oxlade-Chamberlain own goal when the ball hit the midfielder after David Ospina had stopped Josip Pivaric's initial effort.

Arsene Wenger's side lacked cutting edge throughout the first period and things got worse just five minutes before the break as their main goal threat was removed when Giroud was shown a second yellow card for a challenge on Ivo Pinto.

Arsenal started the second period well as they looked to make up for their disastrous first half, and after Mesut Ozil's low strike was saved well by Eduardo the German thought that he had found a leveller, only to see his tidy finish correctly ruled out for offside.

The mini-revival was brought crashing down just before the hour mark, however, when Junior Fernandes rose highest to power a header past Ospina and leave the Premier League side teetering on the brink of a calamitous start to their European campaign.

Wenger made a triple change with 25 minutes remaining in an attempt to salvage something positive from proceedings and it yielded a goal when one of the substitutes, Walcott, beat his man all ends up to collect Alexis Sanchez's pass and slot home on the ground where he scored a hat-trick for England seven years ago.

It was not enough for Arsenal, however, as they slipped to a disappointing defeat against the Croatian champions, who had lost 13 of their previous 15 Champions League group games.