chuck didnt look himself in that fight, got one bombed and that was the end of him but chuck aint no flop, he's arguably the best striker in the game, rashad did look very good and big things are gonna come from him in the future.
It's true up until the ko the match was a stalemate and any fighter can get caught like chuck, he could still come back imo, it's not that chuck has lost it, it's because everyone has figured out how to fight someone like chuck - a counter puncher with excellent takedown defence. Rashad didn't go for the takedown and decided to stand with chuck but didn't come at him much as he knew chuck would counter with one of his punches, so he exploited chuck's low hands and managed to catch him hard. Rashad did the right thing by peck and running and using superior movement until Chuck got impatient and then when Chuck recklessly got a step too close he gut unloaded on. I think a few other fighters will be able to expose this chink in Chuck's armor, but it doesn't mean he's finished (unless of course he decides to retire)