Man Utd skipper Vidic knows he faces test against Man City's Aguero
It will be the first time Vidic has faced El Kun.
"I have never faced Aguero before, not even when he played for Argentina," he said. "We have watched some highlights of him. You are talking about a top-class player.
"Sometimes, it takes time to come to terms with the Premier League but he has found his form very quickly and scored immediately. That tells you what kind of player he is and they also have Edin Dzeko, who has had a very good start to the season. This is a derby game, between the two top teams in the English League; it would be ridiculous if you were not excited."