Yeah, at the end of the 10th they both threw right hands and Smith caught him high on the temple. For some reason I remembered it happening in the 12th and that there was a good 20 seconds left in the round. I was wrong. Bivol was definitely hurt by the shot as would any other fighter that got caught on the temple by a guy like Smith.
I used to think Bivol was too slick and that Beterbiev didn't have the conditioning to thrive in deep waters, but I've changed my mind. I think Bivol's lack of power leads to him getting worn down and stopped late.