Fértoli first appeared in the first-team of Argentine Primera División side Newell's Old Boys during the 2013–14 campaign, he was an unused substitute for a 3–2 defeat to Arsenal de Sarandí on 4 May 2014.[2][3] He made his professional debut in February 2016 against Rosario Central, before scoring his first goal two appearances later in a 1–0 win over Huracán.[2][4] In his first two seasons, Fértoli made twenty-two appearances and scored five goals for Newell's Old Boys.[2][5] In January 2019, Fértoli completed a move to San Lorenzo for $1.6m; signing until June 2020.[6][7]