Wu won against Isner to be the first Chinese atp tour winner. 6-7 7-6 7-6. 5 break points all match and none made. Takes some steely nerve to beat Isner like that.
If Isner had ever managed to develop a significantly better general / return game, plus kept that serve, just think of what he could have achieved over the years.
But I am guessing he has put in the work and pretty much maxed out on his abilities and that serve has taken him a pretty long way over the years.