Manchester City's shock Champions League loss at home to Lyon was not down to Pep Guardiola's absence or a poor atmosphere at the Etihad Stadium, says Mikel Arteta.

City, rated among the favourites to win this season's Champions League, went down 2-1 in Wednesday's Group F clash with Arteta deputising on the touchline for the banned Guardiola.

Maxwel Cornet and Nabil Fekir struck first-half goals for the Ligue 1 side and although Bernardo Silva gave City hope, the Premier League champions could not complete the fightback.

And Arteta would not blame the loss of Guardiola or a low attendance for his side's poor showing in their opening group encounter.

"I have no idea. The reality is Pep wasn't here and we lost the game," Arteta told a news conference. "If Pep would have been on the touchline I can't tell you if we’d have won 5-0 or lost.

"We were very aware of Lyon's strengths and weaknesses. They were well prepared. We weren't prepared to be 2-0 down at the break, but you have to react.

"There is zero margin for errors in the Champions League – you make a mistake and you are punished. If you don't win duels, play simple balls, you will suffer - today was another example of that.

"Sometimes in a new competition you have to get on track. The start wasn't good. We didn't feel the flow around the team."

The Etihad Stadium's top tier was sparsely populated but Arteta would not blame a seemingly disinterested crowd for City's defeat.

FERNANDINHO: MANCHESTER CITY "HAVE TO BE HUMBLE"

"I wouldn't like to use that as an excuse," Arteta added. "We've had this type of crowd in the Champions League before and we've won the games.

"The ideal scenario is to have a full stadium every time and have people supporting the team like crazy. Some weeks that does not happen but it is not an excuse."

Bruno Genesio was left to toast a famous victory for Lyon but the coach demanded his team maintain their performance levels against Marseille in their next Ligue 1 game.

"I'm not sure it’s the greatest feat the club has ever pulled off but it is an achievement," he told reporters.

"Across the entire 90 minutes I think it’s well deserved. We are extremely proud but that is not the only thing we want to achieve this season.

"We want to follow this up in our domestic league on Sunday against a team who are also capable of playing in the Champions League.

"Nabil showed our captain is back. I know I can count on him absolutely. He played a decisive role in tonight's victory. He made a goal, scored a goal and led by example.

"He helped to get our team up the pitch. He also won a few fouls. But this is a team's victory, a collective victory."