Vietnam are considered the weakest team in the group, as the others are all placed above them in the futsal world ranking.
Five-time champions Brazil are currently the second-strongest team in the world, followed by the Czech Republic (16th) and Panama (37th).
Vietnam have just ascended one place in the world ranking to 43rd after beating Lebanon in the playoffs last week to qualify for the Futsal World Cup.
They have only played Brazil once. It was a friendly in 2013 and the team won 3-2.
The world cup group draw, held on Tuesday night at the Home of FIFA in Zurich, Switzerland, was conducted by Jaime Yarza, FIFA Director of Tournaments, assisted by futsal legend Kike, two-time Futsal World Cup champion with Spain in 2004 and 2008, and Edgaras Jankauskas, the first Lithuanian footballer to win the UEFA Champions League with Porto in 2004.
FIFA has ensured that no group has more than one team from the same confederation.
The Futsal World Cup 2021 will kick off in Kaunas, Vilnius and Klaipèda, Lithuania on September 12, with the final set to be played on October 3.