The 21-year old striker made his starting debut two weekends ago in the local derby against Corinthians' arch-rivals Palmeiras, scoring twice to help the club to a 2-1 win.
Three days later he came off the bench in the first leg of the Copa Libertadores final in Buenos Aires and grabbed the goal that brought his side level 1-1 with Boca Juniors.
That goal has made Corinthians favourites to lift their first ever Libertadores trophy when the sides line up for the return leg in Sao Paulo's Pacaembu stadium on Wednesday.
Corinthians are in the final for the first time, while Boca are in their 10th, seeking a seventh win that would bring them alongside fellow Argentines Independiente as the most successful team in the competition.
However, while Boca have the experience, Corinthians have the form.
They are unbeaten in the tournament so far and have conceded just four goals in their 13 matches.
For all that, they still have trouble scoring and have drawn uncomplimentary comparisons with Chelsea, who beat attack-minded Barcelona and Bayern Munich on their way to winning the Champions League this year.
Like the Londoners, Corinthians put organisation ahead of flair and like to pack players behind the ball.
Romarinho could be the answer to their goalscoring problems. The youngster fulfils all the requisites of a Brazilian footballing hero. Son of a poor family whose father cut sugar cane for a living, he was rejected by several top teams before finally coming good at lowly Bragantino.
Corinthians snapped him up last month after he scored six goals in 23 games in the Paulista State Championship earlier this year.
Although his name means little Romario, he is not related to the former Brazil striker turned federal Congressman, even if he reportedly shares the same penchant for nightlife and killer instinct in front of goal.
"Romarinho is cool, he's ice cold, and he had already showed that in the game against Palmeiras," coach Tite said after the Boca Juniors match.
"He's deadly, you just have to give him the ball in the last third of the field to let him do what he knows how."
Both teams will be at full strength for Wednesday's decider.
Boca Juniors did not play at the weekend because the Argentina Clausura tournament is over, while Corinthians' match against Botafogo was postponed to allow the team to prepare.