Rolando Chilavert's Inti Gas crashed to a surprise 3-0 defeat at Real Garcilaso on Sunday - the club's first league defeat since June.
Inti Gas' loss opened the door for Juan Aurich and Cesar Vallejo, who were both victorious on Saturday.
Juan Aurich overcame visiting Melgar 3-1, while Cesar Vallejo edged Union Comercio 1-0 on the same day.
Inti Gas remain top of the standings with 21 points from 11 games, just one point ahead of Juan Aurich (20, +10), Cesar Vallejo (20, +7) and Melgar (20, +6).
Real Garcilaso, meanwhile, climb to sixth in the standings on 16 points.
Sunday's clash at the Estadio Inca Garcilaso de la Vega pitted two teams with contrasting form.
Real Garcilaso were without a win in three games, while Inti Gas had won four matches and drawn two since losing 3-0 to Sporting Cristal.
But it was the out-of-form Real Garcilaso that would emerge triumphant courtesy of Ramon Rodriguez's first-half brace.
Rodriguez got the ball rolling in the 24th minute, volleying the ball into the bottom corner of the net.
The 37-year-old was at it again 10 minutes later, springing the offside trap before lifting the ball over Inti Gas goalkeeper Mario Villasanti.
Real Garcilaso put the result beyond doubt two minutes into the second half, when Juan Lojas stooped low to head home a corner.
At the Estadio Elias Aguirre, Edgar Balbuena, Rodrigo Cuba and Hernan Rengifo were all on the scoresheet as Juan Aurich downed Melgar.
Johan Vasquez was on target for the visitors.
Cesar Vallejo emerged triumphant over Union Comercio thanks to Luis Cardoza's 12th-minute strike at the Estadio Mansiche.
In other results over the weekend, nine-man Universidad San Martin and fifth-placed Universitario, who also had a player sent off, played out a thrilling 3-3 draw.
Kleyr scored twice as cellar-dwellers Sport Huancayo accounted for Cienciano 3-1.
A 90th-minute goal from Carlos Garcia helped third-bottom San Simon to a 2-1 win over UTC Cajamarca.
Fellow strugglers Alianza Lima claimed a 2-1 win at home to Sporting Cristal and Leon de Huanuco prevailed 1-0 against second-bottom Los Caimanes.
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