Mertesacker: Not understandable, not acceptable

Per Mertesacker says Arsenal’s 3-2 Champions League defeat to Olympiacos as “not understandable” and “not acceptable”.
The Gunners sit bottom of Champions League Group F after falling to Greek champions Olympiacos, and face an uphill battle to qualify with back-to-back clashes against Bayern Munich next up.
Mertesacker, who came on midway through the second half in place of Laurent Koscielny, was at a loss to explain the defeat, saying the Gunners “lacked discipline” at the Emirates.
“We lacked that concentration and it is not understandable why we drifted and did not do the job we are used to doing,” he said.
“That is not acceptable and we will be punished [for that] in the Champions League.”We need to get behind the ball and play better defensively. We lacked discipline, even when you get a goal back don’t rush yourself.
“Get your discipline back and with possession you get your chances. If we are not disciplined and do not chase the ball we have got no chance.”