[1] Born in Haedo, Buenos Aires Province,[2] Mareco won the South American Under 20 Championship in 2007.

[3] Thanks to this victory, he received a direct award of the title of International Master the following year.

In 2012 he tied for first place in the Argentine Chess Championship, finishing second on countback.

[7] In 2017 he won the Marcel Duchamp Cup in Montevideo with a perfect score of 9/9 points.

[8] In 2018 he won the HDBank Cup International Open in Hanoi, Vietnam[9] and the Hogeschool Zeeland Tournament in Vlissingen, the Netherlands.