The Gunners gave champions United a guard of honour before yesterday's 1-1 draw.
"We are rivals. Look, at the end of the day we decided to sell him. We are rivals. You want us to make a guard of honour and to respect the champions, then you have to accept as well that respect exists after the game. You want to give absolutely everything during the 90 minutes and after the game you can still talk to each other," said Wenger.