O'Grady wasn't durable enough to go the distance with Shane. Sean never saw that type of speed and power, and was stopped by far lesser fighters. He handled Kenty (a sick Kenty), but Hilmer Kenty wasn't Shane Mosley.
Mosley has become underrated with time. People sell him short because he wasn't Leonard, Jones, or Robonson. He wasn't as good as those guys, but he was pretty special at 135. Way out of O'Grady's league.