[3] In 2015, Lillini began working as a technical assistant in the Chilean team San Luis de Quillota, accompanying Mario Sciacqua.
[6] Due to his knowledge of the club's academy, Lillini was appointed as interim manager of the UNAM first team on 23 July 2020, replacing Míchel, who resigned the day before.
[7] Due to the good results shown and the youth soccer development policy, on 17 August, he was ratified as manager for the rest of the Torneo Guardianes 2020.
After getting the Liga MX runner-up in the Apertura 2020, Lillini qualified UNAM for the 2022 CONCACAF Champions League, in the international tournament Mexico's team reached the final after eliminating the clubs Saprissa, New England Revolution and Cruz Azul.
However, in the last series UNAM was defeated by the American team Seattle Sounders FC with an aggregate score of 5–2, being the first time in 17 years that Mexico was not champion of the most important club competition in CONCACAF.