McGregor has gassed in UFC fights early enough and those fighters are nowhere near the class of Mayweather, nor are they fighting him in a sport in which he doesn't specialise. You could stage slowing down but he was clearly blowing, that wasn't staged that was him having run out of steam. The referee had to step in, he was offering nothing back and it was going to get dangerous. McGregor's reputation will rightly be enhanced, even if he offered very little, because he stuck in there for so long and Mayweather now has a lot of money to blow again.