Define "beaten"? Box office? Avengers already has. Public opinion? Avengers again (or at least a draw) Critical response..Avengers again, with another draw basically. (This coming from a guy that didn't like the Avengers that much, but it still is what it is.) Your opinion? Maybe not, but some folks I know wouldn't rank TDK in the top ten for comic movies, so opinions vary. The Oscar Award? Who knows? We can't sit here and say no other comic movie will ever win a best actor Oscar.
No you are wrong. At least on the critical response, IMDB has Dark Knight ranked at the 6th best movie ever, Avengers is number 158.
Public Opinion and box office, sure the Avengers has beaten Dark Knight; but critically? Based on how good the film is? no not at all.