Justin absorbs way too many punches against strikers that are slower, has less technique and power. Now he's facing MJ who is very fast, has excellent hands, leg kicks and far superior foot work. While Justin obviously has a great chin, he relies on it way too much and a guy like MJ could punish him hard for that.
I see people refering to the Nate fight but Nate is a much different fighter compared to Justin. Nate has a good jab, good at controlling the range and slips punches very well. MJ actually did very well in the first round where he mixed it up and landed both punches and some hard leg kicks. Eventually, Nates trash talk got to him and MJ just started head hunting and abandoned his leg kicks all together just looking for the one punch KO blow and this is, in my opinion, why he lost the fight against Nate.
I would cap MJ at -200 if it wasn't for the fact that Justin CAN wrestle, I dont think he will, but he COULD. It's hard for me to find any area where Justin has the advantage over MJ besides wrestling. My prediction is MJ round 1 KO.