U.S. Open champion Juan Martin del Potro was knocked out in the first round of the Japan Open, losing 6-4, 6-4 to French qualifier Edouard Roger-Vasselin on Tuesday.
Roger-Vasselin set up triple match point with a crosscourt backhand then wrapped up the match in one hour, 28 minutes when Del Potro's forehand return was long.
"I didn't play my best tennis today," said No. 1-seeded Del Potro. "I wasn't feeling 100 percent and the other guy played a great game."
Roger-Vasselin, ranked 189th, had nine aces against the fifth-ranked Argentine's six.