Brazil, who have still never beaten Uruguay away in a competitive game, stayed second in the 10-nation World Cup qualifying group with 24 points from 13 games. The top four teams qualify directly for Germany in 2006 and the fifth plays off against the Oceania region winners.
Uruguay had opened the scoring four minutes into the second half. Brazil goalkeeper Dida failed to hold Ruben Olivera's low shot and Forlan, who scored twice when the teams drew 3-3 in Brazil in 2003, scored from the rebound.
Brazil weathered the storm and equalised in the 68th minute. Lucio headed on a corner, Luisao's shot was saved by Uruguay keeper Sebastian Viera and Emerson, possibly in an offside position, bundled the ball in from close range.
Uruguay coach Jorge Fossati described Brazil's equaliser as a referee's mistake.
"We had the world champions on the ropes," said Fossati, whose team are fifth in the qualifying group with 16 points from 13 games. "We could have won but we ended up with a draw because of a referee's mistake, and when they score that way it hurts more."
The goal gave Brazil new momentum and they looked the more likely winners late on. Ronaldinho was closest with a dipping freekick which was tipped over by Viera eight minutes from time.
Meanwhile, Argentina lead the qualifying group with 28 points. A 65th minute Hernan Crespo goal inspired them to a 1-0 win over Colombia last night.
Argentina, who also included Manchester United's Gabriel Heinze, are now close to securing their World Cup place.
Another United player, Ruud van Nistelrooy, scored his first Dutch goal since his long injury lay-off as Holland won 2-0 against Armenia last night to remain on top of Group One with 16 points after six matches.
Holland are one point clear of the Czech Republic, who won 4-0 in Andorra. Milan Baros scored his 19th goal in 28 internationals in his last game before Liverpool's Champions League quarter-final first leg tie against Juventus at Anfield next Tuesday.
Baros is suspended for Saturday's home game against Bolton following his red card against Everton earlier this month.