Sometimes, there are mountains that are too tall for even the greatest to climb. And that's what happened to Canelo Alvarez as Dmitry Bivol's size, skill, activity and tight defense turned back the Mexican superstar's attempt to collect more world titles with a brilliant performance that ended with a unanimous decision victory at T-Mobile Arena.

Bivol retained his WBA (Super) light heavyweight championship as he refused to bow down to Canelo's pressure and was technically sound enough to prevent making mistakes for Canelo to capitalize upon. Instead of being in awe of Canelo, Bivol (20-0) used a stiff jab and kept busy whenever Canelo became aggressive. Canelo's power was evident but Bivol made sure very few punches landed clean as Canelo bounced power shots off his arms and gloves throughout.

Early on, Canelo (57-2-2) attempted to walk down Bivol but the Russian sniffed out the strategy and would shoot the jab and carry a right hand behind it to keep Canelo from settling in with his power. As the rounds wore on, Canelo was unable to break down his opponent and found himself in a real fight by the middle rounds. Whenever he did land a big power shot, Bivol would tighten his defense up and ensure he wouldn't absorb another shot.

Bivol fought like he had the judges against him and keep throwing into the championship rounds. He caught Canelo flush several times but never seemed to have the 31-year-old in any real trouble. However, the points were piling up and Canelo couldn't get the knockout or definitive rounds he needed.

With scores of 115-113 across the board, Bivol pulled off the big upset as a 5 1/2 to 1 underdog. Not only that, he dashed the possibility of Canelo-GGG in September as Canelo stated he wanted an immediate rematch.