Vietnam's number one badminton player, Nguyen Tien Minh, left the Olympic games after losing 2-0 to Indian rival Kashyap Parupalli on Tuesday.
After a hard-fought 2-1 win over the 54th-ranked Belgian Tan Yuhan on Saturday, Minh needed another win to finish on top of Group D and advance to the second round.
Though the 29-year-old Vietnamese was ranked 11 in the world, his 24-year-old Indian competitor (ranked 21) took a decisive victory.
Minh lost 9-21 in the first set; his redoubled efforts in the second set could not stop the Indian player from cruising to a 21-14 win.
This was the last chance for Minh at an Olympic event but he failed right in the first round, like he did four years ago at the 2008 Olympics when he was also considered to be among the world's top players.
Fencer Nguyen Tien Nhat lost 9-15 to Kazakhstani fencer Alizhanov Elmir in the qualifying round of the men's individual epee contest.
Nhat, the flag-bearer of the Vietnamese sport delegation at the opening ceremony on July 27, was ranked 230th in the world while the Kazakhstani athlete is the world's number 4.