Oscar De La Hoya on Chuck Liddell Knockout, 'Surprised But Not Shocked'

Ring rust is real -- and Chuck Liddell is living proof ... so says Oscar De La Hoya.

The head of Golden Boy Promotions -- which put on the Chuck Liddell vs. Tito Ortiz 3 -- was in a pretty great mood after the fight on Saturday ... telling us, "Tito looked amazing!"

Of course, Ortiz floored Liddell with a brutal 1st-round knockout in Chuck's first MMA bout in 8 years.

"Chuck's timing was off," Oscar said ... "That's 8 years of inactivity."

Oscar wasn't buying the criticism that Chuck shouldn't have been in the cage in the first place -- he thinks Liddell was ready -- but Tito's game is on another level.

So, what's next for Oscar? He's dead set on moving forward with another MMA fight and told TMZ Sports he's looking to sign big fighters ASAP, as long as they're a free agent.