I'm sorry to see Rafa go out so early but Dustin played a great match and deserves the win. Stunning netplay from him.
Rafa's vulnerable against big hitters/servers these days, but even more so on grass. If he wants to make another challenge for Wimbledon, he'll need to avoid these types of players in future years I think.
He now has a well established habit of crashing out of Wimbledon against players outside the top 100. It must really be getting to him.