The last 5 rounds were a beat down? That's a fantasy.
Rounds 1-2 were extremely close. I gave them to Canelo.
Rd. 3 was a toss up at the time, but the stats indicate GGG landed more jabs and power punches.
Rds. 4-5 were clear for GGG.
Rds. 6-7 were Canelo's best of the fight and succinctly won. Here he looks like the better athlete and fighter, accurately tagging GGG when he'd try to open up his combinations and stalking him around the ring.
Rd. 8 saw Canelo own the first minute before being soundly outboxed for the remaining 2/3.
Rd. 9 is where Canelo started to show visible fatigue, lunging and winging. However, I gave him the round because he landed the better shots.
Rd. 10 GGG landed some of the fight's best shots. Outworked, outboxed and landed better shots on a weary Canelo.
Rd. 11 Canelo looks a shell of himself in terms of punch velocity. This is the first time either man is ever backed to the ropes, with GGG advancing on Canelo in the end of the first minute. Overall, GGG outworks him but the damage even after Canelo rallies in the last minute and a half.
Rd. 12 Alvarez fights valiently through his fatigue but it causes him to dip his head into three nasty uppercuts, the best shots of the round and among the best of the fight.
By my count, if you give Canelo round 3 or 11, it is a draw. I'd score each a 10-10 before I'd consider them as Canelo's. It's far more difficult to explain how he lost them than how he won them.