India, Aug. 20 -- Young Garret Tan had already booked his flight out of India for Friday.

He may now have to change it.

The 18-year-old American produced the biggest win of his young career on Wednesday, knocking out former World Championships bronze medallist Lakshya Sen 19-21, 21-19, 21-17 in a pulsating second-round encounter.

Tan had arrived at his maiden World Championships with little more than the ambition of playing his best badminton. He now has a place in the pre-quarterfinals and, at the very least, another day in New Delhi.

"I was supposed to leave on Friday, but I guess.," Tan said with a smile.

For a teenager making his World Championships debut, it was an extraordinary introduction to the biggest stage.

Tan did not sp...