Manchester City assistant coach Mikel Arteta admitted his side had only themselves to blame for their shock 2-1 defeat against Lyon on Wednesday.
With City manager Pep Guardiola serving a touchline ban, it was Arteta in charge as the Premier League champions suffered a dismal start to their Champions League campaign.
Tipped as favourites for the European title, error-prone City were well below their best.
First-half goals from Maxwel Cornet and Nabil Fekir punished mistakes from City duo Fabian Delph and Fernandinho.
“We saw two very different halves. We conceded many counter-attacks and at this level you get punished,” Arteta said.
“If you give cheap goals away it is difficult.”
Despite their sloppy performance, Arteta was adamant City would have been worthy of a draw if they had snatched an equaliser.
“In the second half we dominated and played in the opponents’ half and created many chances,” he said.
“I still believed we could do it. We reacted really well. On another day we could have come back.
“The subs affected the game but sometimes it is too late.
“It is disappointing. We are usually strong at home. Now you have to go and win away from home.”
City are the first English team to lose four successive Champions League matches, a run that includes last season’s three knockout-stage defeats against Basel and Liverpool.
Bernardo Silva’s second-half strike gave City hope of a fightback, but their inconsistent efforts spluttered out.
Silva admitted City had lacked their usual high tempo and desire.
“The first half we were not at our best. We didn’t press with the same intensity we usually do,” he said.
“They scored two goals, then in the second half we tried to go after the result.
“We were not good enough. And unfortunately we did not want to start this way in the competition but it is what it is and we have to look to the next games.”