Arsene Wenger feeling heat after painful night for Arsenal at Dinamo Zagreb
Dinamo Zagreb 2-1 Arsenal
Arsenal had striker Olivier Giroud sent off as they slumped to a disappointing 2-1 defeat in their Champions League Group F opener at Dinamo Zagreb.
The France forward missed a couple of early chances before collecting two needless cautions in the first half.
Dinamo took the lead against the run of play with an own-goal from Alex Oxlade-Chamberlain after the ball bounced back off him past goalkeeper David Ospina, who had saved Josip Pivaric's shot.
After Giroud's dismissal on 40 minutes, Dinamo doubled their lead through a powerful header by Junior Fernandes.
Despite a late goal from substitute Theo Walcott, Arsenal were left to reflect on another frustrating European away performance.
Gunners boss Arsene Wenger said: "It is not the way we wanted to begin the competition. We were a bit unlucky. We faced a Zagreb team who were committed. We gave it all until the end but unfortunately couldn't come back.
"The first yellow for Olivier Giroud is a foul for us and the second is an accident. They got away with obvious fouls many times.
"We have enough games to come back. We focus to win our next home game and I'm sure we can beat Zagreb at home."
Wenger, perhaps with one eye on Saturday's trip to Chelsea, made six changes from the team which had beaten Stoke, including a start for Ospina
On 24 minutes, Dinamo went ahead against the run of play.
Pivaric was played into the left side of the Arsenal penalty area inside Mathieu Dubuchy. His near-post effort was saved by Ospina, but cannoned back into the net off Oxlade-Chamberlain.
Arsenal's evening got worse five minutes before half-time when Giroud was sent off.
The France striker, who had already collected an earlier caution for dissent, tripped Daniel Ivo Pinto, which gave Romanian referee Ovidiu Hategan little option but to issue a second yellow card followed by a red.
It was 2-0 on 57 minutes when Fernandes got above three Arsenal defenders to head home a left-wing corner at the near post.
Wenger had seen enough, and soon made a treble substitution as Walcott, who once scored a hat-trick for England here, Francis Coquelin and Joel Campbell all came on.
Walcott reduced the deficit on 79 minutes when he produced a cool finish after sprinting clear.