Nguyen Thi Anh Vien set a new personal best at the World Swimming Championships, which closed on August 9 in Kazan, Russia.
Vien swam in the women's 400m dividual medley with a time of 4min 38.78sec, her best ever time.
The result was much better than her time of 4:39.65 when she took a bronze medal at the Asian Games in the Republic of Korea last year.
It is also better than Vien's Southeast Asian Games record (4:42.88) that she established in June in Singapore.
However, Vien failed to qualify for the world's finals, as she ranked No 10, overall, in Kazan.
She will now travel to Moscow to take part in the FINA World Cup on August 11-12, and then swim in another Cup competition in Paris on August 15-16.
She will return to the US to continue her training on August 18.
Earlier, all Vietnamese athletes completed their competitions at the world championships.
They did not, however, meet their targets of winning an A-standard for a berth to take part in the Rio de Janeiro Olympics next summer.-VNA