A week after lifting their maiden Apertura title, Juan Aurich were back in action as they saw off San Simon 2-1 at the Estadio 25 de Noviembre on Sunday.
Hernan Rengifo, who scored nine goals in 15 Apertura games, opened the scoring after 32 minutes in Moquegua.
The 31-year-old was left unmarked at the back post and coolly headed the ball into the corner of the net.
Osnar Noronha doubled the visitors' lead on the stroke of half-time, when he sprung the offside trap before poking the ball beyond San Simon goalkeeper Federico Nicosia.
San Simon were given a glimmer of hope after substitute Matias Sen pulled a goal back in the 68th minute but Juan Aurich held on for all three points.
Melgar, Universitario, Sporting Cristal and Los Caimanes were also victorious on the opening weekend.
Runners-up behind Juan Aurich, Melgar were 2-0 winners at Cienciano on Saturday.
Bernardo Cuesta and Omar Fernandez were both on target for Melgar at the Estadio Inca Garcilaso de la Vega.
German Alemanno's 57th-minute goal helped Universitario to a 1-0 success at Sport Huancayo on Sunday.
Goals from Sergio Blanco, Carlos Lobaton and Irven Avila inspired Sporting Cristal to a 3-2 victory over 10-man UTC Cajamarca.
Union Comercio were beaten 1-0 at Los Caimanes on Monday.
Meanwhile, Leon de Huanuco and 10-man Real Garcilaso drew 1-1 on Saturday.
