For 20-year-old Chung, who is 78th in the ATP rankings, the victory is one of the biggest of his career.
"I didn't play my best tennis," said the dread-locked French star who has been out three weeks with an Achilles injury.
"But he (Chung) was simply too good for me today."
"It wasn't a good game from me, but that's how it is after a long time away," he said.
For 20-year-old Chung who is 78th in the ATP rankings the victory is one of the biggest of his career.