I notice that Donald Young is in a rich vein of form. 10 consecutive wins at $100k Challenger level fro the loss of just one set. His ranking has gone from 142 just after the US Open (where he also did well) to 103 this week. Not bad!
He is probably still a bit 'run down' from his tooth problems. Extractions aren't always straightforward and if he had to take antibiotics that could affect him as well.