Mowbray believes Arsenal are one of the favourites to win the Champions League
Manager Tony Mowbray conceded Celtic had been eliminated by the better side after the 5-1 aggregate loss to Arsenal in the Champions League play-off.
And Mowbray refused to criticise officials over a controversial award of a penalty in the 3-0 second leg defeat.
"The referee has given it. But, if the TV pictures show it should not have been given, so be it," said Mowbray of the penalty won and scored by Eduardo.
"Over the two legs, Arsenal had more quality and deserved to go through."
Artur Boruc appeared not to make contact with Eduardo in the run up to the penalty decision by referee Mejuto Gonzalez, with the Croatian striker converting in the 28th minute to open the scoring.
"I have not seen a re-run of it, so I cannot sit here and complain about it," Mowbray said.
"All the boys thought there was no contact, but we have to accept it and move on."
Celtic defender Glenn Loovens added: "I was close enough to get a good view on it. It's disappointing when you concede a goal like that.
"You can see from the reaction of the boys, they were close to it.
"If it stays 0-0, you are in the game, but now we are 1-0 down and the game is over.
"The referee made the decision and he is not going to change it.
Eduardo won a spot-kick after going down in the penalty area
"It is very disappointing, but that is football. It is sad it happened to us and I do not think it is really fair, but it helped his team take the lead.
"There is a ref and a linesman to see those kind of things."
Emmanuel Eboue and substitute Andrey Arshavin put the Gunners into a 3-0 lead at the Emirates before Massimo volleyed a late consolation for the Scottish Premier League side.
"The first goal was always going to be crucial," said Mowbray. "If we had got it, you would have had a more interesting spectacle.
"The fact that Arsenal scored it allows their real high-quality players to relax a bit more and play at their own pace.
"When you try and play high up against such quality players, you are asking for trouble.
"That is the way it panned out - but I could not question the desire and effort of my team."
And Mowbray, whose side now drop into the group stages of the Europa League, expects Arsenal to mount a strong challenge to be crowned European champions this season.
I expect us to compete very well in the Europa League
"I would suggest there are only four teams in the English Premier League of the quality of Arsenal," he added.
"I do not think the gulf between our football club and the rest of the Premier League would be there - maybe we will get the chance to show that in the Europa League.
"I genuinely believe Arsenal are a team who can win this competition, but at the moment Celtic are not in a position to compete with the English sides who make the semi-finals of this tournament year in and year out.
"You have to take the positives out of the way we played in these two matches.
"Hopefully, we will be more than a match for whomever we draw now and I expect us to compete very well in the Europa League."
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