Spanish top seed Paula Badosa fell at the first hurdle at the Pan Pacific Open in Tokyo on Wednesday, losing 6-3, 6-2 to fast-rising Chinese teenager Zheng Qinwen.

World number four Badosa, who was eliminated in the round of 64 at the recent US Open, struggled to gain a foothold against 36th-ranked Zheng and joined number two seed Caroline Garcia in making an early exit from the tournament.

Badosa failed to hit a single ace and lost seven straight games before ending a miserable evening in the Japanese capital by swatting a return straight into the ground on match point.

The 19-year-old Zheng, who reached the last 32 at the US Open, said her win over Badosa was "not a surprise" for her.

"I always know that I have the level," said Zheng.

"It's just when to make it. I'm so happy that I can make this match and I want to repeat it again."

Zheng, who beat Japan's Misaki Doi 6-2, 6-4 in the first round, will now face either Belgium's Elise Mertens or Claire Liu of the United States in the quarter-finals.

Badosa had a bye into the second round.