Eduardo volleyed home the third from point-blank range to complete a 5-0 aggregate rout of the Czech champions and secure Arsenal's place in the draw for the Champions League group stages.
Wenger said: "I find Eduardo more at ease on the left flank where he has the tricks of a winger, whereas Walcott is more comfortable on the right.
"Eduardo is a great striker and you could see that from the way he played against Sparta.
"We did not always have the drive to find our strikers because our main concern was to keep the ball.
"But if you find Eduardo and supply him with chances, he will score goals. He's a box player."