Nam was defeated 6-0, 4-6, 3-6 by No 4 seed Lee Kuan-yi of Chinese Taipei in 2hours and 26 minutes.
Earlier, his fellow Vietnamese Trinh Linh Giang was knocked out in the secondqualification round.
Nam will play with his regular partner Sun Fajing, seeded No 4, in the doublesevent on February 28.
They will face Chinese pair Wang Ruikai and Wang Ruixuan in the firstround.-VNA