This is a great hypothetical matchup... It would depend on how Oscar was able to fight imo... If he tried to box too much and spent too much time looking to set up his left hook KT probably would have timed him from the outside and taken the decision... Kostya was never as effective when someone was able to get inside and apply constant pressure though.. Id call he vs De la Hoya a pickem.... But I definetly think Mosley would have beaten KT at 140 or welterweight... He was too strong and could take KT's best if he needed to. Kostya would not have stood up to Mosleys constant pressure imo.