The Gunners kick-started their European campaign with a vital win against Pep Guardiola’s German champions thanks to goals from Olivier Giroud and Mesut Ozil.
It is very easy to raise your game for Bayern Munich, but it is the two previous games that have cost them
Arsenal are three points behind Group F leaders Bayern ahead of their return trip to Allianz Arena after their earlier losses to Dinamo Zagreb and Olympiacos.
Keane described Arsenal as soft and lacking leaders following their shock 3-2 loss to the Greek side at The Emirates earlier this month.
And the former Manchester United captain hasn’t been swayed despite their win against Bayern.
“They’re still soft,” Keane told ITV Sport.
“Just because they beat Bayern Munich [doesn’t change that]. I thought they’d get a result. They were desperate for a result.
“I’ve said all along they’re a top quality team going forward, but they rode their luck again last night and the goalkeeper made some good saves.
“They’ve still got a lot to do to get out of the group.”
Keane, who part of Sir Alex Ferguson’s squad that won the Champions League in 1999, added that Arsenal need to be more consistent against the lesser sides in Europe’s top tier competition.
“They have to do it more often,” Keane added.
“Even the manager said some European games, he’s not sure if the team is up for it.
“It is very easy to raise your game for Bayern Munich, but it is the two previous games that have cost them.”
Arsenal remain bottom of Group F with three points after three games.
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