The Brazil international striker opened the scoring in the 11th minute and doubled the visitors' advantage nine minutes before half-time.
Felipe Anderson made it 3-0 in the 54th minute, before Neymar staked his claim for the match ball with Santos' fourth goal eight minutes from time.
Third-placed Gremio overcame the dismissal of Julio Cesar to defeat Ponte Preta 1-0.
The red card came 19 minutes from time - but the hosts overcame the setback to win thanks to Andre Lima's 90th-minute breakthrough.
Figueirense's struggle continues, the second from bottom team went down to a 71st-minute goal from substitute Vidal Hernane at Flamengo.