LOS ANGELES– When E.J. Singler hit a three-pointer with 2:55 to play to give No. 21 Oregon a 75-65 lead over USC last night, it looked like a sixth straight win for the Ducks was safely tucked away and the team could finally begin contemplating Saturday’s tantalizing Top-25 matchup against league-leading UCLA. But an energized Trojan squad, playing its first …