Sao Paulo, however, did worse, losing 3-1 to Portuguesa after goalkeeper Rogerio Ceni missed a penalty with the score 0-0.
Brazilian champions Flamengo opened their defence of the Carioca (Rio de Janeiro) state championship with a 3-2 victory over Duque de Caxias in front of a small crowd at the Maracana.
Corinthians, without big guns Ronaldo and Roberto Carlos, went in front against promoted Monte Azul when new signing, 35-year-old striker Iarley, headed home Souza's cross in the 15th minute.
Their little-known opponents from the interior of the state equalised three minutes later when Rafael Fefo lobbed goalkeeper Tiago Cardoso.
Corinthians are counting on Ronaldo, who led them to the Paulista and Copa Brasil titles last year, and Roberto Carlos, signed from Fenerbahce earlier this month, to help mark their 100th anniversary by winning the South American club crown for the first time.
Sao Paulo captain Rogerio Ceni missed the chance to increase his record of 84 goals as a keeper in the 26th minute when his penalty was saved by opposite number Fabio. Brazil midfielder Hernanes blasted the rebound over the bar.
Sao Paulo did take the lead seven minutes before halftime with a shot from outside the box by former Hertha Berlin and Brazil forward Marcelinho.
However, Portuguesa turned the match round in the second half with two goals from Heverton and one by Marco Antonio.
Flamengo, who won the national title in December in their final match of the Brazilian championship in front of a crowd of 90,000 at the Maracana, drew only 16,000 fans with a near reserve team without Adriano or new signing Vagner Love in their attack.
After changing ends 1-0 down, Flamengo scored through former Manchester United midfielder Kleberson, Chilean Gonzalo Fierro and new signing Fernando, who hit the winner five minutes from time.
The Libertadores Cup starts in late February and the Brazilian championship in May before it breaks until mid-July for the World Cup in South Africa where Brazil will start as one of the favourites.
