Guerrero arrived at Universitario in 1995, recommended to the club by José Luís Chilavert.[4] He debuted for Universitario in the 11th round of the 1995 season on 12 May,[5] in a 3–0 victory against León de Huánuco. In the following fixture, he conceded 6 goals in a derby against Alianza Lima which ended 6–3.[2]