Duong played great, especially in the last two sets. But he also made enough mistakes that Filler should have won.
As I said in another thread, Filler has been slightly more erratic since the WPA-WNT spat. Obviously still a threat to win every tourney he plays in. Obviously still one of the top three players in the world. But he does seem less ... invincible (For that matter, so has Gorst this year).
It could also be just that it's the rising quality of players. Not just the young guys, either.
Hoang was a very good player a few years ago, but he was borderline top 50. At best. Yet he's become arguably a top 10-15 player worldwide by playing so much on the international scene. His safety play and tactics used to be a sore spot. Not so anymore. And his jumping is now elite. It wasn't two or three years ago.
Great crowd.