The Gunners crave cup success as they bid to end an eight-year trophy drought.
Keen said: "Arsenal are under a bit of pressure because they've not won a major trophy for a while.
"I think it's a good draw for us because the crowd will get behind us. I like the game."
"You can't knock Arsene's achievements," he said. "He has been magnificent and has been working under financial restrictions and they have come through that. With Mesut Ozil joining, they are going to be up there."