"The U" have eight points from four matches, one more point than Brazilian champions Flamengo, playing without striker Adriano who is nursing a back injury. Chile's Universidad Catolica have three points and Caracas FC of Venezuela two.
The match, played some of the time in torrential rain, was postponed from Wednesday due to flooding at the Maracana as storms that have caused mudslides and killed about 100 people wrought havoc in Rio de Janeiro this week.
Argentines scored Universidad de Chile's goals with midfielder Walter Montillo heading them into a 1-0 half time lead from Jose Contreras's right cross and compatriot Rodriguez securing a surprise draw with a powerful shot as the Flamengo fans were celebrating a victory.
Midfielder Michael equalised in the 67th minute from Vagner Love's pass and right back Leo Moura appeared to have settled the match in Flamengo's favour when he put them 2-1 from the edge of the box up with eight minutes remaining.
The Paraguayans' midfielder Rodrigo Burgos was sent off in the 68th minute.
