It was an easy win for Canelo Alvarez, judging from the impressive statistics (55-1-2, 37 KO) he had over Avni Yildirim (21-3, 12 KO). Avni looked like a punching bag for Canelo, it was really obvious that he was outmatched, that is why they didn't send him out again after the 3rd round.
He didn't response from this trainer, it means that the Yildirim doesn't want any piece of Canelo. So instead of sending him for another round of beating, which may eventually knock him out cold and putting his health at risk, Diaz rather stop the fight right there. And I will echo the sentiments of other, it was overly mismatch, I don't think that Yildirim landed a single significant shot at Canelo.
Canelo is more aggressive and from that he landed more solid punch than Yildirim and like what you said, I also tried to watch those available replays and check if there's any solid that's been landed to Canelo.
This was a mismatch no argue with that, the skills and power of Canelo dominated this fight, the only thing that matters is the future of Avni
that's the reason it's needed to stop to avoid further damages, as those solid punch from Alvarez really hurting Avni.
This can lead to some serious injuries if they'll him fighting, best to accept the defeats than force him to continue risking his health.
