re: Someone 'Splain to Me What I Just Saw (our D)

Moist field conditions negated Texas A&M's speed advantage on the outside. Their receivers' ability to make cuts and burn our vulnerable corners was negated. Johnny Football could still get up to straight-line speed, but he couldn't juke or maneuver as well without stumbling or slipping. This slight speed reduction enabled our linebackers (particularly the middle one) to be more capable of keeping up in coverage.

Their offensive line has never been dominant. Our defensive line played with passion and had their best game of the year. With less time to throw, a wet ball, and less ability to evade tacklers, Johnny Manziel made less accurate throws. This led to a reduced completion percentage and 3rd down conversion rate.

LSU's power run game was optimized by the conditions, allowing our larger offensive line to routinely push back their undersized defensive line. This led to more first downs, less pressure on the passing game, fewer incompletions, and more time of possession for LSU. Johnny Manziel can't produce points while his team is on defense.

Short version:
Defense was motivated, offensive game plan was perfect, weather gave LSU an advantage due to scheme.