Seedorf, 37, gave Botafogo an early lead with a shot on the turn from near the penalty spot against opponents who were playing under interim coach Ze Sergio after Guto Ferreira was sacked on Thursday.
Antonio Carlos headed the second before half-time of Saturday evening's game to leave Botafogo with 10 points from five games, two ahead of Cruzeiro, Coritiba and Bahia.
Former AC Milan striker Pato completed his 10th game without scoring as world club champions Corinthians drew for the third time in their first five matches against Portuguesa, leaving them 12th.
Pato has been free of muscular injuries which plagued him in Italy since his move in January but has been unable to rediscover his scoring touch.
Flamengo, who fired coach Jorginho on Thursday, notched their first win of the competition by beating Criciuma 3-0 away with two goals from midfielder Gabriel, the second direct from a corner which crept in at the near post.
Internacional, led by Brazil's 2010 World Cup coach Dunga, were held 2-2 at Cruzeiro, the third draw in their opening five matches.
- Sports & Recreation
- Guto Ferreira