Belichick is hard to beat. He game plans better than anyone else and makes better adjustments.
On offense, NE featured rugged backs Burkhead and Michele because that's what works against the Bills fast, poor tackling defense. Against a big, slow defense they'd have run James White all day. The Bills couldn't counter and so NE controlled the game.
On defense, when Singletary has an effective first half. (7 rushes for 34), NE adjusts to stop him in the 2H (8 rushes for 12 yards), yet Bills don't adjust and continue to pound him for no gain series after series.