Aubameyang was left out of the starting XI for the north London derby after he arrived late for the squad’s meet-up before the game.
Mikel Arteta and the club captain held ‘really positive talks’ in the days that followed with the striker back in the starting XI for Thursday’s Europa League clash against Olympiacos.
Arsenal progressed into the quarter-finals of the competition but fell to a 1-0 defeat on the night with Aubameyang enduring a disappointing evening in front of goal.
And Keown believes the 31-year-old was still feeling the mental affects from what happened at the weekend.
Speaking to BT Sport, Keown said: ‘We learned that Aubameyang was suffering tonight, I think it affected him at the weekend, being left out of the team.
‘It wasn’t the Aubameyang we know and love. It’s one of those, yes you sweep it under the carpet and look forward to the weekend and you start to build but it was a really poor night for Arsenal in terms of their performance.
Arsenal fell to a 1-0 defeat to the Greek giants but progressed into the next round 3-2 on aggregate.
They will learn their quarter-final opponents in Friday’s draw.