Selecting between the two on GOAL's TiKTok channel, the former Real Madrid star chose his old club's player as the most vital to Brazil's current squad, preferring Vinicius to Barcelona's Raphinha.
Of his decision, Marcelo said, "Vini is the most complete player". He also turned down the opportunity to pick other Brazilian stars, such as Gabriel Martinelli and Savinho.
WHAT ELSE DID MARCELO SAY?
Marcelo was also asked to pick his star of this season's Champions League, turning down the likes of Bukayo Saka and Desire Doue before settling on PSG's Ousmane Dembele. The Frenchman was key to his side's European title and Marcelo said he "enjoys a lot" his performances.
Both Raphinha and Vinicius are in the Brazil squad to take on Ecuador and Paraguay in World Cup qualifiers this month, with ex-Real Madrid boss Carlo Ancelotti now in charge of the Selecao.