The 20-year-old, known as "Gabigol", had featured sporadically and failed to find the net over the course of six forgettable months in Italy since moving to San Siro from Santos.
But the Rio 2016 goal medallist came off the bench to tap home from close range in the 81st minute on Sunday, sealing a 1-0 win for Stefano Pioli's side at Stadio Renato Dall'Ara, moving them up to fourth in the Serie A table.
High-flying Roma are on the agenda next for Inter, while Gabriel has to make good on a culinary promise he made to his team-mates.
"In the locker room they said Gabigol would offer a Brazilian-style dinner to everyone when he got his first goal," Pioli told Mediaset Premium.
"I am happy for him. It was hard for him at the beginning but now he can begin to take satisfaction."
And the attacker says he will oblige, though he has suggested a more traditional Italian dish.
When asked if he would be taking the bill, he replied: "Yes. How about a carbonara?"
He added: "I'm so happy with the goal, but more so with the victory. It's a special day for me. I always work hard to help the team and to win."
Inter looked set for a frustrating stalemate at a ground where Napoli won 7-1 earlier this month, but Pioli was pleased by his team's fighting spirit, as they made it nine wins from their past 10 Serie A outings.
"I have a team that believes until the end," he said. "The right opportunity arrived and we were ready to take it.
"We struggled with an opponent that closed down very well. We had no rhythm and were slow, especially in central areas and did not play as well as we know we can.
"The only feeling at the moment is satisfaction at work well done, in seeing what my players give. We must continue, as we've achieved nothing yet.
"It's true nine wins in 10 games is impressive, but the others are pushing hard too and we need to keep up with them."