Rosicky sparks Arsenal hope but familiar frailties sabotage hunt for top spot

The line-up may have changed significantly but Arsenal's malaise continues. Arsène Wenger made seven changes to the team dispatched by Swansea last weekend but defeat to Olympiakos carried all the hallmarks of his first-choice side.

After flattering to deceive for 45 minutes, alarming defensive lapses cost the Gunners here as a fine first-half effort by Tomas Rosicky, pictured, was overturned by goals from Giannis Maniatis and the substitute Kostas Mitroglou.

Arsenal finish second in Group B and face the prospect of their last 16 clash being decided away from the Emirates Stadium. Victory would have been enough, just as Wenger predicted pre-match, after Montpellier held Schalke to a 1-1 draw in France.

Only after the draw for the knock-out stage is concluded on 20 December will the full damage of this result be known in the context of Arsenal's European aspirations – the prospect of another meeting with Barcelona exists – but of more immediate relevance, it did little to dampen the negativity permeating the club.

Rosicky, marking his first start of the season following a tendon injury with his first goal since March, was a positive but whether he is sufficiently ready to reinvigorate the Gunners' Premier League campaign remains to be seen. Wenger has bemoaned his side's lack of creativity – Santi Cazorla appears fatigued after starting all 15 league games to date – but he needs more than a revived Rosicky on this evidence.

Arsenal began brightly. Alex Oxlade-Chamberlain stood a cross up to the back post which Chamakh headed down and after the ball escaped Olympiakos defender Drissa Diakité, Aaron Ramsey had a golden chance, arriving late into the box but completely missing his kick.

The Gunners looked vulnerable at the back but continued to carry a threat and took the lead on 38 minutes. Gervinho charged into a scrum of Olympiakos defenders and somehow dug out a fine pull-back for Rosicky to sidefoot effortlessly past former Manchester United and West Ham goalkeeper Roy Carroll.

Wenger had seen enough to convince him of Rosicky's wellbeing and he was withdrawn at the interval and replaced by Andrei Arshavin, who headed over and then forced a decent stop from Carroll.

But familiar defensive shortcomings reared themselves albeit amid some controversy. Paulo Machado was left unmarked to head against Szczesny's left-hand post with Spanish referee Alberto Undiano Mallenco adjudging the Pole to have made contact with his despairing dive.

From the resulting corner, the Gunners failed to clear and Maniatis forced the ball home. Szczesny was cautioned for his protest. It got worse. Moments after coming off the bench, Mitroglou turned away from Carl Jenkinson and curled a fine 20-yard effort into the bottom corner past Szczesny.

Wenger had no ammunition on the bench to respond and Arsenal's dire run was extended to one win from eight games.