Harry Potter and the Prisoner of Azkaban question?

"Not in James and Sirius's league" is about like saying that he's not in the same league as Chuck Norris, Neville Longbottom, and Izumi Curtis and then wondering how he could defeat small children, muggles, and/or people who weren't expecting an attack. Given the right lever, (and/or wand in the back,) and we don't need no stinkin' strength or talent. Give 'em the ol' razzle-dazzle...