PITTSBURGH -- Pittsburgh's Jabaal Sheard-led defense forced a fumble that led to a touchdown and never allowed Louisville's ineffective offense to generate any momentum during a 20-3 victory Saturday that kept the Panthers unbeaten in the Big East. Ray Graham and Dion Lewis ran for scores in the second half as Pittsburgh (5-3, 3-0) scored the game's only two touchdowns after settling for a 6-3 halftime lead on two Dan Hutchins field goal. Louisville (4-4, 1-2) never mounted a scoring drive after Chris Philpott kicked a 35-yard field goal on the game's opening series. The Cardinals, held to 185 yards on 55 plays, also were hampered by Bilal Powell's right knee injury that sidelined the nation's No. 4 rusher for all but two plays of the second half.