He will be physically stonger and what I meant by bigger is that he was a career long Lightweight whereas Marquez fought most his career at feathweight. Both guys had tough fights against lesser fighters than each other.
You have to also consider Marquez when he got to lightweight is more hittable, doesnt move his legs as much and lost some hand speed. This is Johnston at his best weight, he is also a southpaw will take Marquez best shot and will be more elusive.
Marquez is the greater fighter, just stylistically I see Johnston dealing with him better than the other way around
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