Ly Hoang Nam, the first Vietnamese to win a Grand Slam title in July, has improved his position by 255 places and is now number 1,055 in the world.
Earlier, the highest ATP ranking of the 18-year-old tennis player was 1,242 on July 13, when he and Indian Sumit Nagal won the Wimbledon boys' doubles in London.
Nam went on to reach the semifinals at the Egypt F27 Men’s Futures in Egypt last month.
The new ranking is a milestone for Nam’s pursuit for professional tennis career, coach Christian Brydniak said.
Nam said he aims to improve his position further to be qualified for tougher events like the Challenger Tour.
Nam and Brydniak left Vietnam on August 31 to prepare for US Open, his last Grand Slam boys' category.
He said he aimed to advance to quarterfinals in boys' single.