So to recap: in the most difficult game of Arsenal's season, against the team that Arsène Wenger agreed were the best in the world, the manager dropped Olivier Giroud, his regular No9, and pressed Yaya Sanogo in as his replacement.

It took the notion of a fiery baptism to new temperatures. Sanogo, the Bosman free transfer arrival from Auxerre last July, had 127 minutes of football behind him in an Arsenal shirt. He had joined with the reputation for being injury-prone and he has been unavailable for almost all of the season because of a back problem. Until a whole-hearted full debut against Liverpool in the FA Cup win here last Sunday the 21-year-old had virtually dropped off the radar.

Sanogo is an Under-20 world champion with France and it is perhaps worth remembering what Wenger said about him last summer when, for so long and at the time of those loud calls for A-list investment in the squad, he was the only new signing.

"Sanogo will surprise you," Wenger said. "He has not made the headlines because he is not 50-100 million pounds but I am quite confident he will make them."

Sanogo's very selection made waves, coming as it did against the backdrop of Giroud's marriage crisis, which was sparked by the Sun's story about him sneaking a girl into the Arsenal hotel on the night before the Crystal Palace game on 2 February.

Sanogo will tell the grandchildren about the night that he led the line against the mighty Bayern Munich and, when Arsenal started at a blazing tempo, there was the moment when the fairytale nearly played out. Following a seventh-minute scramble the ball broke to him inside the area and, almost in slow motion, he fired his shot at goal. Manuel Neuer saved. It was impossible not to smile and thousands of Arsenal supporters did.

But Bayern are not the types to accommodate the plucky underdog and Sanogo did not have his day. The game passed him by from about the 25th minute and, if his evening was summed up by the yellow card he received for chasing down but catching Neuer in the 55th minute, Arsenal's fans were left to wonder how they could have entered a knockout tie against the European champions with an untested rookie up front.

They have relied upon Giroud, almost exclusively, all season but this seemed like the night when their lack of depth in the position finally came back to bite them.

Wenger stuck hard to the line that Giroud had been omitted for footballing reasons, rather than as punishment for breaking the club's rules before a match (and subsequently telling half-truths about what had happened).

Neither, Wenger went on, was the decision based on Giroud's psychological state as he resides in the dog house. "When I play Giroud every game, people reproach me and, when I rest him, people reproach me," Wenger said. "It was just a decision because of recent games. He is a bit tired. Giroud is a strong character and what happened hasn't influenced his behaviour on the pitch."

Giroud has shouldered an immense physical burden as, very often, the only recognised, fit centre-forward. The club's dependence on him has been enforced, partly because of injuries to Lukas Podolski, Sanogo, Theo Walcott and Nicklas Bendtner and also because of the failure to sign the big-name striker they chased throughout last summer.

It should also be said that Wenger clearly does not have faith in Podolski up front. The former Bayern striker was an unused substitute here and there were no prizes for guessing how he felt about that.

Giroud has struggled to score of late but it was hard to believe that the timing of his demotion had nothing to do with his mind-set, in terms of the strain that the cheating revelations have placed on his relationship.

He has issued public apologies to his wife, family, Wenger and Arsenal and, earlier in the day, he said, via his Twitter account, that he had not committed adultery. To paraphrase a US politician, he did not have sexual relations with that pin-up girl.

Would Giroud really have made a difference? The only thing that could be said with certainly was that Sanogo was fresher and he gave everything. On a night like this it was never going to be enough.