The 21-year-old started ahead of club team-mate Mauro Icardi on Thursday and headed home for a goal on his full debut in the Albiceleste
Lautaro Martinez could not hide his delight after scoring his first Argentina goal in Thursday's friendly rout of Iraq, while looking forward to the upcoming clash against Brazil.
Argentina, now unbeaten in three games following a disappointing World Cup, will next face the Selecao
The Inter forward headed home after 18 minutes in Riyadh, where Argentina dominated throughout and extended their lead via second-half goals from Roberto Pereyra, German Pezzella and Franco Cervi.
As well as giving Martinez his first start for Argentina, caretaker coach Lionel Scaloni fielded an inexperienced side in the absence of Lionel Messi, Gonzalo Higuain and Sergio Aguero.
Martinez told reporters: "These players are growing in confidence to match their team-mates.
"It is important to score on my debut. It is important to win to gain confidence and keep improving.
"We are coming up against a very difficult rival: Brazil. We have to keep working so we can give our best. Tomorrow we will see and analyse how Brazil play."
#NuevoDesafío Final de la primera etapa!@Argentina con gol de Lautaro Martínez, supera a#Irak por 1 a 0.pic.twitter.com/CSf7UJ2RUB — Selección Argentina (@Argentina)October 11, 2018
Iraq coach Srecko Katanec said his players lacked fitness after seeing them fall away towards the end of his second game in charge.
A 2-2 draw with Kuwait in Katanec's first game as coach had offered Iraq some hope of a positive display against more illustrious opposition, but they were pinned back for long periods in either half.
"Clearly we are behind physically," said Katanec. "The guys need to work on their physical preparation. We need to be 30 per cent better than we are now.
"The first half was not so bad defensively, they scored a goal where there was no chance and they didn't create any clear chances in the first half.
"We stayed too far from their players and we were not aggressive enough. If you are not physically prepared then you may be afraid, and maybe we showed too much respect."