The midfielder told City's website: "Benjani is flying and has been since he started training with us. His first session was brilliant and he will be a big asset to us I am sure.
"He holds the ball up well and allows runners to go past him and that is one of the big things about playing on your own up. It gives the midfielders the confidence to fire balls into him. He is also quick and strong.
"I think new players arriving always freshens things up and that they will both have an impact."