Is this prime Sergio or the crippled Sergio who fought Cotto? the latter doesn't last 20 seconds of the 1st round
Excluding the crippled one I'd say it's a close call but I'm leaning towards Barkley. He has similar power (maybe a bit more, but they're in the same ballpark), a longer reach, which will help with the jab and control distance, and he's a warrior who can get up off the floor come back and win. But whoever wins it wouldn't be a huge upset either way.