And head coach Carlo Ancelotti confirmed afterwards that Neymar is on track to be available for the final group game against Scotland.
Matheus Cunha scored twice, in the 23rd and 36th minutes, before Vinicius Junior added a third in first-half stoppage time, finishing after being played through by Lucas Paqueta.
Neymar, 34, has been managing a calf strain and has not played a top-flight match for Santos since 17 May.
Ancelotti gave an update on his recovery timeline at the post-match press conference.
"Neymar will train individually tomorrow, and on Monday he'll train with the rest of the team," Ancelotti said. "He'll be available for the match against Scotland."
Injuries limited Neymar throughout Brazil's qualifying campaign, but he was influential whenever he did play, contributing two goals and three assists in four appearances.
Ancelotti also addressed Cunha's role as a makeshift centre-forward, with the Manchester United player scoring both first-half goals having started in place of Igor Thiago.
Asked whether Cunha would continue in that role, Ancelotti left the door open.
"It could be," Ancelotti said. "I think Matheus's position was good for creating problems for the defence. And he played his passes through really well, and his position was good to be effective in attack. It could be an option. We talked about it yesterday. I don't want a fixed identity. We might change this for the next match."
Cunha had come off the bench in the 61st minute of Brazil's 1-1 opening draw with Morocco before starting against Haiti.
Brazil sit top of Group C on four points, ahead of Morocco on goal difference after the Atlas Lions beat Scotland 1-0 earlier on Friday. Scotland, who have three points, now face Brazil in a match that could determine their World Cup future, though Ancelotti insisted his focus remained on his own team's performance.
"We're not thinking about eliminating Scotland. We're thinking about playing well and improving, and we're analysing the match," Ancelotti said. "If we can reach top spot in the group, that would be important for the future. So we want to prepare well for that match."
He added that Scotland should not be underestimated.
"Scotland has its own characteristics. They can create a problem. Today they created problems for Morocco. So we have to focus on the match, stay calm, keep our composure and keep working to improve," Ancelotti said.