Zagreb (Croatia), Sep 17 (IANS): Arsenal manager Arsene Wenger lashed out at the referee after his team was defeated by Dinamo Zagreb in the opening match of their Champions League campaign here.

The English Premier League (EPL) giants were off to the worst possible start in their hunt for European glory when a first-half own goal by Alex Oxlade-Chamberlain and a second half strike by Junior Fernandes condemned Arsenal to a 1-2 defeat in the Group F encounter at the Stadion Maksimir here on Wednesday evening.

Walcott pulled one back for the visitors late into the match.

Arsenal's misery was compounded in the 40th minute when forward Olivier Giroud was sent off for a second booking when he fouled Dinamo right back Ivo Pinto.

Wenger was livid with referee Ovidiu Hategan after the game.

"We were a bit unlucky. We had a lot of the ball and, as well, we had early chances. I believe the first goal is offside and after that, the sending-off is very harsh.

"We were not at our best but nor was the referee. Dinamo stopped us (unfairly) in situations without being punished -- counter-attacks where we had to play 10 against 11 in one half, very strong situations," Wenger was quoted as saying by BT Sports.

The visitors were let down by Giroud's performance on the night. The France striker wasted a couple of scoring chances and let frustration get the better of him when he was booked for dissent after his reaction to the referee blowing for a foul against him.

It proved crucial as he was then sent off for a second bookable offence when he caught Pinto with a late challenge after 40 minutes, as Arsenal's failure to sign a striker in the summer transfer window again came into focus.

Wenger however, refused to criticise the centre forward, preferring instead to train his guns on the referee.

"The first yellow (for Giroud) is a foul for us and the second is an accident. They got away with obvious fouls many times. We have to take it on the chin.

"Yes, he (the referee) was rash (with the second yellow card). The first yellow is Giroud's fault because he protested -- even if it was not a foul against him. He should not have responded to the referee. But the second, he is unlucky to touch the guy. I don’t understand the referee," the 65-year-old said.

"I don't think on the second yellow, Giroud saw him (Pinto). It was accidental completely. But it happened. I thought at that moment it was not a second yellow. It has to be on purpose, a foul on purpose. He should have given many yellows tonight."