The Manchester City man has already scored nine Premier League goals this season, netting four times in one match against Tottenham Hotspur.
And former Arsenal defender Keown feels Aguero is harder to defend against than Man United forwards Wayne Rooney, Robin van Persie or Radamel Falcao.
When asked during a 'Tackle Keown' session on the Daily Mail's website which striker he would least like to defend against, Keown said:
"I think Aguero, for me. He is a darting player with a lot of explosive power. He twists and turns and just when you think you’ve got him he’s away. He’s very strong so you can’t knock him off the ball and he gets so much power with little or no back lift.
"Once he’s gone past you he makes it easy to find the net. You have to get tight because he can shoot around you but if you get too tight he’s away from you.
"Falcao always wants to play on your shoulder and you’d have to be alert from crosses because he loves running across the face of you to score goals. Van Persie is changing because he’s not turning and running at his opponents as often. I’ve played and worked with him and he’s got really good pace.
"I think Rooney is now better in a deeper position so he can arrive in the box to finish. Playing in that area is almost finishing off his football education and he could end up in a midfield, almost a bit like Scholes."