As best I could tell, only one Super Bowl XLVI commercial had a boxing relation, but it was one of the early ads in the game. Hyundai went to the Rocky well with theme song "Gonna Fly Now" by Bill Conti:
One of my favorite commercials of the night, honestly.
"Gonna Fly Now" remains one of my favorite tunes and one of the songs I most associate with the sweet science. I know it's kind of corny and Rocky has its detractors in the boxing community, but it's one of my favorite movies and one of the things most responsible for making me a boxing fan in the first place. The sequels are all garbage (yes, yes, I know, Drago and Mr. T, blah blah blah) until Rocky Balboa, but the original movie is a legit classic.
If only Stallone hadn't crapped on his original fine vision with a bunch of useless sequels to pad his bank account. He did the same thing with the Rambo character, of course. I wish he'd gotten to make a bunch of Demolition Man sequels.