Arsenal was eliminated from the FA Cup third-round tie after losing 1-0 to Nottingham Forest on Sunday.
Lewis Grabban’s late goal ensured Forest defeated Mikel Arteta’s side and qualified for the FA Cup fourth round.
Speaking on ITV, Keane said, “Obviously Forest are at home, you are thinking “come on get on the front foot, get balls into the box, get bodies in there”.
“Arsenal, for all of their quality, they look like Real Madrid, but they are playing like a pub team, it’s been so poor. Pace of pass, decision making, passing it behind people. Really… rubbish.
He added: ‘You make the point that they played really well last week against Man City. But they lost the game. There is still a softness.
“We are watching the game here live and, okay, they are missing players – but you are still looking thinking, “Arsenal are here for the taking”.
“They didn’t show any sort of presence about them, they didn’t turn up here saying “We are Arsenal Football Club, we are going places”. Obviously, there is a feel-good factor around the club, but that is a big setback for the club today.”
Arsenal’s next game is against Liverpool in the EFL Cup semi-final tie on Thursday.