Wenger’s side crashed to a 2-1 defeat at Olympiakos on Tuesday that ended their hopes of pipping Schalke to first place in Champions League Group B and condemned them to a daunting draw in the last 16.
Arsenal would have taken pole position with a victory in Athens as eventualy group winners Schalke were held to a 1-1 draw by Montpellier.
But they wasted that lifeline in typically careless fashion as Olympiakos scored twice in eight minutes in the second half through Giannis Maniatis and then Kostas Mitroglou to overturn Tomas Rosicky’s first half opener.
It was another blow for Wenger, who is coming under increasing pressure from the club’s fans following Arsenal’s worst start to a Premier League season in his 16-year reign.
The Gunners, currently 10th in the league after Saturday’s woeful 2-0 home defeat against Swansea, have now won just two of their last nine matches in all competitions and Wenger concedes they need to bounce back against West Bromwich Albion on Saturday to ease the sense of crisis engulfing the club.
“It is a good opportunity for us to keep focused and to show strength and unity. That is what you want to do in the next game,” Wenger said.
With the January transfer window less than a month away, Wenger has been linked with a host of players, including Schalke forward Klaas-Jan Huntelaar and Crystal Palace winger Wilfried Zaha.
But the Frenchman, who sent out a weakened team against Olympiakos, refused to be drawn on whether he would ship out some of his underperforming stars and bring in new faces.
“I feel the young players, you discover them in these kind of competitions. They have the quality,” he said.
“We have a strong squad, but in certain areas we are a bit short because we cannot rotate.
“We will see where we stand on January 1 and see what we do.”
After seven years without a trophy and such a patchy run of form this season, Arsenal harbour only the slenderest hopes of winning the Champions League, but even that might have been extinguished by this loss.
Finishing second in the group means a tough test will lie ahead in the last 16 and even Wenger admitted they are up against it.
“We need a good Christmas present now (in the draw), but we will see,” he said.
“We can get a bad draw or less strong team, but you normally get strong teams through anyway now.
“The disadvantage we have is we play the second game away, but that is not statistically proven to be a such a disadvantage.
“Let’s see, but for now it is important for us to focus on the Premier League, forget about the Champions League a little bit and get ourselves back in decent form in the championship.”
To add to Wenger’s woes, Olympiakos cancelled out Rosicky’s opener in controversial fashion when they were wrongly awarded a corner which led to Maniatis’s close-range strike.
“We also got a very bad decision against us on the goal. I am not against the fifth referee, but you would like at least for them to be concentrated on their job,” Wenger said.
“(Arsenal goalkeeper) Wojciech Szczesny was far away from the ball. Why didn’t the fifth official tell the referee? It’s difficult to understand, to concede a corner when it doesn’t go off the goalkeeper.”
Meanwhile, Olympiakos coach Leonardo Jardim will lead his side into the Europa League after finishing third in the group.
“We just had to focus on getting the win, to become one of the top seeds for the Europa League and to play well in front of our fans, so I am pleased we achieved both of these aims,” he said.