Naw bro he was tired in the 5th, and eventually couldn't keep that Monster from advancing on him. No angles to escape, and when Alex throws that jab the only smart choice is to shoot for a takedown. Of course when your tired in the 5th and not an offensive grappler, you'll probably skip on a shot.
He fought brilliantly, far far better than anyone else would have in a standup fight. But if Izzy's brutal kicks, thudding counter shots, great cardio and elusiveness isn't enough to stop Alex. NOBODY is gonna last with him on the feet.
Izzy isn't a very good boxer, but his ability to angle off has made him extremely hard to beat. The pressure was otherworldly from Alex, he didn't allow Izzy to escape for free. Izzy was smashing his leg into him, jabbing him, going to the body, mixing up his kicks, even clinched several times and got him down, but eventually it was too much.