Time management unimpeachable, tie management distinctly problematic. Pierre-Emerick Aubameyang arrived at the Emirates Stadium promptly on this occasion but Arsenal’s progress to the Europa League quarter-finals was far less straightforward than it should have been. It would be an exaggeration to say Olympiakos came close to outdoing the turnaround they completed here last season but they caused Mikel Arteta’s team what felt like an unnecessary headache, scoring early in the second half through Youssef El‑Arabi and exerting enough pressure after that to prevent them seeing matters out in total comfort. For the second time in five days Arsenal made a significant stride in their season while showing a brittleness that, whenever it rears its head, offers a stark reminder of how far they must still go. They had made it to half‑time untroubled beyond a Bernd Leno save from El-Arabi, diverting the ball wide off his knee, and given Olympiakos required three goals it should have been plain sailing from there. But they began the second period sloppily, as if unaware the Greek champions had an extra gear to discover, and had already sailed close to the wind when El-Arabi found his bearings. Not for the first time, Arsenal were too open when a move broke down deep inside the Olympiakos half and, after Giorgos Masouras fed him, the centre-forward was able to cut into the box and beat Leno via a deflection off Gabriel. It was a haunting by the ghost of traumas past, given El-Arabi had scored the Greek champions’ dramatic winner 13 months ago, but despite the backing of a boisterous delegation Olympiakos were unable to make their subsequent spells of pressure count and faded after Ousseynou Ba was dismissed late on for two quick bookings. “What we’ve done with the ball, in particular, is nowhere near the standards we’ve set ourselves and we made it really difficult,” Arteta said. Even so, Arsenal had enough chances to extend their aggregate lead by several. Aubameyang had been returned to the starting lineup after his weekend indiscretion – a move that showed Arteta was taking the second leg with high seriousness and that any issues had been smoothed over – and he should have scored at least twice. Midway through the first half he toepoked over, perhaps having got the ball stuck slightly beneath his feet, after being played in by Dani Ceballos; there was an altogether more glaring miss as the clock ticked down when, with the whole Olympiakos half to run into and perhaps too much time to select his finish, he chipped wide of José Sá’s left post. “I hope the weekend isn’t still on his mind,” Arteta said. “We moved on, he started and we expect, when he does play, that he performs at the level he can.” In fairness, Aubameyang was denied brilliantly by Sá at the death. Arteta pointed to “four, five, six” chances to make things safe, other culprits including Nicolas Pépé and the substitute Martin Ødegaard. Their radar did not need to be on point this time, but harder assignments surely await.