Neymar plays only 12 minutes as Brazil held by Nigeria
The 27-year-old striker was replaced by midfielder Philippe Coutinho after feeling an injury in his left thigh.
Brazil doctor Rodrigo Lasmar said Neymar stopped feeling any pain after the match and will go through more tests in France when he's back with his club Paris Saint-Germain.
Nigeria midfielder Joe Aribo opened the scoring in the 35th minute after dribbling past Marquinhos in the penalty box.
Brazil leveled in the 48th through a shot from midfielder Casemiro after he got to a rebound from a header that hit the bar.
Neymar walked normally to the dressing room. He threw a shirt to fans and gave them a thumbs-up as he left.
Neymar missed this year's Copa America because of a right ankle injury. He only returned to action two months later.
The Brazilian also had a right foot injury in January playing for PSG. The problem in his fifth metatarsal kept him off the field for almost three months.
Neymar struggled with injuries ahead of the 2018 World Cup in Russia which affected his performances in the tournament.
The friendly in Singapore could have marked Neymar's rise to second all-time Brazil top goal scorer. He has 61 goals, one less than two-time World Cup winner Ronaldo.
After lifting the Copa America title in July, Brazil drew 2-2 with Colombia, lost 1-0 to Peru and tied 1-1 with Senegal on Thursday.
"This is a time in which we need to test (new players)," said Brazil defender Marquinhos. "But we have to find our pattern as soon as possible."
Coach Tite had tried to use Neymar in midfield, replacing Coutinho, but the striker's injury made him quickly change plans.