Gustavo Ariel Guerreño Otazú (born 17 October 1991) is a Paraguayan footballer who plays as a forward for Chilean club San Marcos de Arica on loan from Deportes Concepción.
Born in Paraguarí, Paraguay, Guerreño was with club 15 de Mayo in his hometwon before joining the Rubio Ñu under-20 team.
He made his professional debut with them in the 2010 Paraguayan Primera División against Guaraní under Francisco Arce.
[4][5][2] In the second half of 2018, Guerreño moved to Chile and signed with Deportes Melipilla, getting promotion to the Chilean Primera División in the 2020 season.
[9][10] In May 2024, he moved on loan to San Marcos de Arica to replace Nicolás Gauna due to an Achilles tendon rupture.