Fluminense laid on a huge welcome for former Chelsea and Portugal midfielder Deco on his debut in the Rio derby with Vasco da Gama in front of a crowd of 80,000 at the Maracana but the leaders were held 2-2.
Corinthians cut Fluminense's lead to two points with a 3-0 win over Sao Paulo in their city derby.
After 15 rounds, "Flu" have 33 points and Corinthians 31 with Botafogo and Ceara completing the top four, seven points further back.
Neymar, who said he would stay at Santos for five more years after his club turned down a 20 million euro offer from Chelsea, put Santos ahead just before the hour when he converted a penalty after a hand ball by Mineiro's Werley.
Danilo scored the second from Neymar's pass to put Santos on 21 points in sixth place with a match in hand.
"It was just another game, I had to play well, but it was like a new start," the 18-year-old Neymar told reporters. "I had a good match, I scored a goal and gave the pass for another."
Paulista (Sao Paulo) state and Copa Brasil winners Santos were inundated with offers for their talented young players and they transferred forward Andre and midfielder Wesley to European clubs but managed to keep Neymar.
"I'm happy with my growing status as an idol. That's what I wanted here at Santos," Neymar said.
"My happiness is being able to stay at home. I've been here (at Santos) for six years and that (fact) won out."
Deco, playing his first league match in the country of his birth after 13 years in Europe where he became a naturalised Portuguese, could have crowned his debut with a goal and victory in the "clasico", but with only the goalkeeper to beat in the 87th minute, he blasted his chance over the bar.
The derby marked the temporary closure of the lower stands at the Maracana for their refurbishment for the 2014 World Cup, reducing its capacity to 40,000 until the end of the year. After that it will be closed altogether for further work.
Corinthians, watched by former coach Mano Menezes who left last month to take the Brazil job, produced a good performance in their win over Sao Paulo with two goals from midfielder Elias and the other by Jucilei.
