Conteh should win but he was a bit of a hard luck fighter at the championship level. I don't think Ward wins but I could see his style troubling Conteh at times and making it appear a bit closer than it really is.
I think his jab and handspeed would give Ward fits. Ward would have success on the inside but Conteh would make him pay to get there. Conteh had to sweat down to make 175 so his size and strength could nullify some of Ward's work inside. At his best Conteh handles Ward. Ward's best shot is against the Conteh of the Matthew Saad Muhammad fights. He was having trouble with his conditioning and desire to fight by then. Ward might have a better chance against that version.
Ahumada was a good and tough fighter and Conteh just took over in the second half of the fight... terrific performance Ahumada was unlucky like Yaqui Lopez after him and Pierre Fourie before him... guys that would've been champs in weaker eras who came up with repeat title shots against exceptional champs
