Simple answer: Length, Combination Punching, Boxing IQ & A general belief that he could beat AlvaRoid.
Long answer: Bivol has better physical dimensions than AlvaRoid & wasn't afraid to use them unlike others (*cough Callum Smith *cough) . He wasn't afraid to throw combination punches in spot where he could (for example when AlvaRoid was try to bait him in the ropes) because he knew if he sensed any danger he could use his longer legs to maneuver away & AlvaRoid would be overcommitting on counter punching which would have put him in harms way. He also was thinking much faster than AlvaRoid was, he said multiple times anytime AlvaRoid threw big punches he'd have to step back and get his breath back, in those moments Bivol would capitalize by throwing combinations to make it more difficult for AlvaRoid to do so & finally Bivol actually believed he could win unlike AlvaRoid's last few opponents who if we're being honest lost before they stepped in the ring.
Like I stated in previous post: "The only fighters that could actually beat AlvaRoid are Bivol & Benavidez." Last night you saw just that. If there is a rematch Bivol wins even easier.
in addition to the boxing and moving
I was impressed by Bivol standing inside to counter Alvarez with left hooks
a European holding his own inside against a Mexican
Once he knew he could take the power, it was over. I'd definitely like to see how Bivol fares against AlvaRoid at 168 (If he wants it).
bivol has a higher ring IQ than all those other guys. Kovalev was skilled but slow and shot, he did pitty pat punches to avoid being countered. Bivol is canelos same age, his natural punching speed and power was there. We seen his chin is good with smith.
His defense was very good, canelo couldnt break him down couldnt get to him. BJS and Callum tried to run but they couldnt stop all body shots they got broken down. BJS was pretty low ring IQ, he had some moments but canelo was shooting that upper cut from the opening rounds and BJS didnt adjust for it.
Canelo tried every which way to get around bivols guard, hooks, splitting it straight through and the upper cut and he just couldnt penetrate it.
There isnt another active guy out there at 168 and below that could do what bivol just did. Canelo needs to go back down and take those fights, he aint a light heavyweight, we seen a shot kovalev pull his punches these other light heavies aint pulling their punches.
Nice analysis, its very true...Canelo's patient and load-up style would eventually get exploited by a guy who not only that the legs to get away and a good jab, but also fights at a higher pace and can take the power(which was Bivol)