Arsenal head coach Unai Emery wants his players to learn how to operate with 10 men but insists there are no disciplinary issues in his squad despite another red card in the Europa League defeat to Rennes.
The Gunners had started the game well and led through Alex Iwobi's third-minute cross-cum-shot – only for things to go wrong once Sokratis Papastathopoulos picked up two bookings in a seven-minute spell.
Rennes drew level immediately after the dismissal as Benjamin Bourigeuad struck a stunning equaliser before the Ligue 1 outfit dominated the second half and a Nacho Monreal own goal and a late Ismaila Sarr header secured a 3-1 victory at Roazhon Park.
Arsenal now have it all to do in next week's second leg if they are to progress to the quarter-finals and Emery felt the sending-off changed the game more than his side should have allowed it to.
"I think we changed more than we want, but a red card can come," he said.
"Two yellow cards and it's the referee's decision. After, I think we must learn to play – when it's coming like today – with one less player on the pitch.
"Not a good experience today, because we couldn't do our work in difficult moments, in difficult minutes, with one less player, like we wanted. I think we can do better."
Arsenal had Lucas Torreira sent off in Saturday's north London derby draw with Tottenham and Alexandre Lacazette missed the Rennes game – and will sit out the next leg alongside Sokratis – after he was dismissed in the previous round against BATE Borisov.
Emery does not believe there is a discipline issue in his squad, simply replying "No" when the question was put to him.
He backs his side to overturn the scoreline at the Emirates Stadium next Thursday, though.
"We can analyse these three red cards individually," he added.
"I am positive in the first 40 minutes because I think, with respect to them, we imposed our gameplay in these moments.
"We can maybe score a second goal because we deserved to, but after it is really very different in the match.
"But we are going to think, for the next week, we are going to start 11 against 11, without Sokratis and without Lacazette, but we have players.
"Like the first 40 minutes, we can do it with our supporters also, to have the possibility to come back.
"But we know this result is not good. It is bad and it is going to be tough for us. But we need to focus and with our players, there is a possibility to come back."
For Rennes, a side competing at this stage of a European competition for the first time, it was a famous win.
Ticket applications could have sold out the 29,778-seater stadium three times over and the atmosphere before, during and after the game was electric.
Midfielder Benjamin Andre knows the tie is not over and called on Rennes to put in another top-quality display in north London.
"We did exactly what we had to do," he said.
"We put them under a lot of pressure. We showed a lot of enthusiasm and the atmosphere was extraordinary. We'll have to produce the best performance possible at Arsenal to qualify."
