Choose who will win
I am actually tempted to nsay Karnak here.
With his ability to detect weakness, he could almost bypass the Rhino's armoured costume and attck him directly.
His mastery of martial arts enables him to nerve strike etc and his enhanced agility and endurance mean that he should be able to stay ahead of Rhino for long enough to get the job done.
Karnack has all the abilities he would need to be a top competitor, his ability to detect weaknesses are underestimated, which is a weakness of his writers and anti-fan's. I think Karnack is more than capable to beat Rhino. Although he is not as strong he is faster more agile and his attacks are critical or even fatal. How dangerous is someone who's attacks are almosted garunteed to be critical strikes?
Long reign the underestimated pound for pound badddest fighter in the game Karnak!!!!!