Mike Leach's Air Raid offense didn't disappoint in its SEC debut on Saturday as Mississippi State upset defending champion LSU 44-34, and quarterback K.J. Costello set a conference record for passing yards in a  game with 623. The previous record was held by Eric Zeier of Georgia, who threw for 544 yards against Southern Miss in 1993. Costello came to Mississippi State this offseason as a graduate transfer after starting 25 games in three seasons at Stanford. His previous career high for passing yards in a game was 381. Costello's 623 passing yards against LSU were the 11th most in FBS history, and the most in a player's debut. His 60 pass attempts are the most by a Mississippi State quarterback. LSU, which lost 17 starters from the team that went undefeated last season, became the first defending national champion to lose its season opener since Michigan in 1998.