Universidad Chile top the table, level on six points and plus-four goal difference with Santiago Wanderers and Huachipato.
Martin Lasarte's men earned a 3-1 win at O'Higgins - powered by a Gustavo Canales brace.
Matias Corujo put the visitors ahead in the 40th minute, before Canales' first of the match made it 2-0 moments after the interval at the Estadio El Teniente in Rancagua.
Fernando Elizari struck with six minutes to play to give the home side hope of arresting their deficit but Canales' second in injury time sealed the three points for Universidad Chile.
Santiago Wanderers came from behind to post a 2-1 win at Cobreloa, with Matias Mier and Jorge Luna scoring goals either side of the half-time break for the victors.
Andres Vilches' 74th-minute goal handed Huachipato a 1-0 win at Universidad de Concepcion, while Union Espanola joined Huachipato in keeping consecutive clean sheets to start the season as they downed Universidad Catolica 1-0.
Milovan Mirosevic struck in the 90th minute to give Union Espanola all three points.
Also unbeaten through two matches, Colo Colo sit fifth after a 2-0 win at home to Deportes Iquique.
An Esteban Paredes brace in the final 20 minutes - the first goal from the penalty spot - gave the hosts their first win of the season.
Union La Calera opened their account in fine style, downing Barnechea 3-0 away from home.
After the match was scoreless through 45 minutes, Leandro Benegas opened up the game for Union - scoring twice within 10 minutes of the re-start before Jean Paul Pineda added the sealing third goal.
Barnechea prop up the table with a goal difference of minus-six through two games.
Also point-less are Cobresal, who were denied at home to Palestino 1-0 by a Leonardo Valencia winner at the death.
Each of Antofagasta and Audax Italiano are scoreless through 180 minutes this season, after playing out a 0-0 draw for their first points respectively this season.
Nublense came from behind to beat San Marcos 2-1, with the match ending in heated circumstances as Jose Rojas (Nublense) and Marco Ciani (San Marcos) were dismissed.
Sebastian Montesinos scored the winner for Nublense in the 81st minute.
