The 24-year-old was named in new Brazil manager Tite’s first squad for their World Cup qualifying clashes with Ecuador and Colombia, with action kicking off on Thursday night.
Taking on Gustavo Quinteros’ Ecuador side at the Estadio Olimpico Atahualpa in Quito, the Selecao started slowly.
Tite left Coutinho out of his starting lineup, instead favouring a four-man attacking unit of Neymar, Willian, Paulinho and Gabriel Jesus.
But with Brazil struggling to find a balance in the opening 45 minutes, with former Tottenham Hotspur midfielder Paulinho particularly passive, Tite looked to gain control in the second half.
The 55-year-old introduced Coutinho on the hour mark, with Liverpool‘s No. 10 replacing Willian, and Brazil picked up a gear.
Allowing Neymar to take up a more focal role, Coutinho’s creativity saw him link up well with the Barcelona star, as well as soon-to-be Manchester City striker Jesus.
With Neymar scoring the opener from the penalty spot on 72 minutes, Brazil were then boosted by Juan Carlos Paredes’ sending off, with the Watford full-back dismissed for two bookable offences.
Coutinho drifted between the lines in a free playmaking role, with Tite’s side dominant in the closing stages.
With Brazil already cruising, Jesus put the icing on the cake with two excellent, late strikes.
His first came with a neat flick past Alexander Dominguez from the edge of the six-yard box, before he turned and fired past the Ecuador goalkeeper from outside the area on 90 minutes.
Coutinho will be hoping his game-changing cameo will have earned him a starting role as Brazil take on Colombia at the Arena Amazonia in Manaus on September 7 (1.45am KO, BST).
Instead the forward will take part in a behind-closed-doors friendly with Huddersfield Town on Friday, alongside a host of the Reds’ finest academy talents.