Who would have beaten a prime Whitaker?

[generalbulldog]

I've watched almost all of his fights except his last 2 where he soundly lost. But in his prime the man's defense and boxing skills was something to behold. Sweetpea never lost in his prime, I don't count the robbery in the Ramirez fight as a loss especially since most have him winning anywhere from 8-10 rounds. And I'm talking about his prime from 1984-1994, from LW to WW.

IMO in boxing history it would be an extremely hard task to have beaten that prime version. But for fun who could have beaten him or made it extremely competitive? Duran? Leonard? Hearns? Mayweather? Trinidad? Pacquiao? Chavez at 135 or 140?