The USC defense turned in the second-best defense in the nation, and some argued one of the best college has ever seen. Through the air, the USC defense held opposing offenses to only 6 touchdowns while collecting 19 interceptions as the best pass defense in the nation, with Mays being a key factor in their success. Though he didn't register an interception throughout his junior season, Mays had a team-leading 8 pass deflections with four of them coming in a week 9 matchup against California which averaged almost 40 points per game to that point. Mays had a spectacular performance in the game, delivering several big hits which jarred balls loose from the receivers' hands. What would have been Mays' first interception of the season was called back on a penalty by Kaluka Maiava. Through regular season play, Mays collected 53 total tackles and 8 pass deflections. The Trojans would go on to face Penn State in the 2009 Rose Bowl, where the defense shut down one of the most explosive offenses in the country in the 38–24 win. A memorable play in the game by Mays was a devastating helmet-to-helmet hit on wide receiver Jordan Norwood which momentarily knocked Norwood out of the game and incidentally his teammate Kevin Thomas as well.