The 18-year-old Vietnamese player was leading 7-5, 1-0 when third-seeded Edoardo Eremin of Italy retired from the match.
In the second round, Nam will face unseeded Cameron Silverman of the United States, who at 1,082nd is 235 places above Nam in the latest ATP ranking. Silverman beat Luis Fernando Ramirez of Venezuela in the first round.
The tournament is part of the International Tennis Federation (ITF) Men's Circuit, which is a series of professional tennis tournaments held around the world.
The ITF Men's Circuit represents the lowest rung of the men's professional tennis ladder.
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