Merentiel made his professional debut on 19 February 2017, starting in a 3–4 away loss against CA Cerro;[4] seven days later he scored his first goal, netting the first in a 2–1 away win against Liverpool FC.[5] On 12 March, he scored a brace in a 2–1 win at Montevideo Wanderers FC.[6]
On 3 August 2017 Merentiel moved abroad for the first time in his career, after agreeing to a one-year loan deal with Segunda División side Lorca FC.[7] The following 31 January, his loan was cut short.[8]
In January 2019, Merentiel was signed by Argentine club Godoy Cruz for a fee around 175.000 euros.[9] On 10 September 2020, Merentiel was loaned out to Defensa y Justicia until the end of 2021 with a purchase option.[10] On 2 January 2022, Defensa triggered the option and signed him on a permanently contract until the end of 2024.[11]
On May 18, 2022, Merentiel signed a four-year contract with Palmeiras.[12] In January 2023, Merentiel was loaned to Argentine club Boca Juniors with a trade option of US$3 million.[13] On 10 November 2023, Boca uses the purchase option.[14]