Some key advice...
#1 Play on Rookie difficulty.
#2 Remember RT is sprint.
#3 Turn Offsides down to 0.
Press start during a game. Go to gamplay options and select off sides, and adjust slider to 0.
When your opponent has the ball, before he hikes it, select one of your defensive men and have him run to the offense side and stand just behind the Quarterback. Don't touch anyone though.
When they hike the ball, immediately tackle him with no penalty for being offsides.
You'll get your 4 sacks, and you'll greatly increase chances of winning the game.
Good luck. I love American sports and know them very well, but I dislike sport video games. This game took me less than 7 hours to complete. That's not bad.