Forlan said playing at another World Cup remains his great ambition, Uruguay having missed out on Germany 2006 after losing to Australia on penalties in a playoff.
"What I've done this season has been a great personal achievement but, as a player and a Uruguayan, I dream of going to the World Cup," he told reporters.
"It's the missing link."
Uruguay, who have 17 points from 12 games in the South American group, are fifth, a position which will earn a playoff against a CONCACAF region team at the end of qualifying.
The top four in the 10-team group go directly to South Africa for the World Cup.
Forlan was in the Uruguay squad on their last finals appearance in 2002 but only came off the bench for the second half of their final game against Senegal.
Although he scored in the 3-3 draw, it was not enough and Uruguay were eliminated.
On Saturday, Uruguay will be missing firebrand captain Diego Lugano and midfielder Cristian Rodriguez as they defend an impressive home record against their larger neighbours.
Brazil's last success in Uruguay was a 2-1 win in the extinct Atlantic Cup in 1976. Since then Uruguay have enjoyed four wins and three draws.
"They know how to use home advantage and they will put us under pressure," said Brazil coach Dunga, whose team are second in the group with 21 points, three behind leaders Paraguay.
"We have to try and keep possession as we have players of quality," he added.
Probable teams:
Uruguay: Sebastian Viera; Maximiliano Pereira, Carlos Valdez, Diego Godin, Martin Caceres; Jorge Martinez, Diego Perez, Sebastian Eguren, Alvaro Pereira; Luis Suarez, Diego Forlan
Brazil: Julio Cesar; Daniel Alves, Juan, Lucio, Kleber; Gilberto Silva, Felipe Melo, Elano, Kaka; Robinho, Luis Fabiano
Referee: Saul Laverni (Argentina)
