The 29 year-old playmaker, who joined Aston Villa on loan from Barcelona in January, netted a sublime long-range strike to make it 2-0 in the 62nd minute.
That goal marked Coutinho's first for his country since October 2020 when Brazil beat Bolivia 5-0 in their opening World Cup qualifier in this campaign.
It was also Coutinho's sixth goal from outside of the area for Brazil during Tite's tenure, with no player having scored more such goals in that time.
Coutinho, who has 65 caps to his name along with 19 goals, was back in the Brazil set-up for a second successive international break after missing much of 2021 with a knee injury, but had not featured for the Selecao since 2020 prior to starting against Ecuador last week.
"I was absent for a long time and I came out of a very complicated injury," Coutinho said. "I was called up for the previous two games for the Brazilian team but I hardly had a chance to play. I received a new opportunity now and I am happy to have delivered.
“I am very happy to have scored again for the Brazilian national team and to have scored again in this stadium with the Brazilian fans present."
Coutinho started and played 73 minutes in an offensive Brazilian formation, sitting behind a front three of Vinicius Junior, Matheus Cunha and Raphinha, with Neymar absent.
Lucas Paqueta and Coutinho offered plenty of attacking threat from midfield too but Brazil coach Tite cooled excitement about the formation being a permanent fixture despite piling on four goals, with Raphinha and substitutes Antony and Rodrygo – the youngest player to score for the Selecao in this qualification campaign – also on target.
"I don’t believe much that the team is more offensive by having three strikers," Tite said. "I see football as a balance.
"Those offensive players can only create if they have a creative midfield behind.
"A balanced team takes possession of the ball more times. I do not conceive of football where the pieces do not have harmony."