Chile Wrap: Uni. Chile only unbeaten side left
Martin Lasarte's men were 3-0 winners on the road at Antofagasta, courtesy of a Sebastian Ubilla brace.
The 16-time Primera Division champions sit clear top with a maximum 12 points, clear of Santiago Wanderers and Union Espanola (both nine).
Wanderers were 2-0 winners at home to Deportes Iquique, with Ronnie Fernandez sealing the win with a 90th-minute goal before being sent off shortly after.
Union Espanola are third, goal difference behind second-placed Wanderers, after downing Union La Calera 2-0.
Colo Colo's unbeaten start to the season came to an end, after going down 3-2 at home to O'Higgins.
The hosts in Santiago de Chile led twice, with Juan Delgado and Esteban Paredes scoring either side of a Braulio Leal effort for the visitors in the first half.
But O'Higgins came home with a wet sail, as Luis Valenzuela and Octavio Rivero scored in the final 20 minutes to deliver the three points to Facundo Sava's men.
Colo Colo remain fourth in the table, level on seven points with Huachipato, Palestino, O'Higgins and Nublense.
Nublense earned a 2-1 win at home to Universidad Catolica despite playing for over a half with 10 men.
Boris Sagredo put Nublense ahead in the 22nd minute, however team-mate Jose Rojas was shown a red card 14 minutes later.
With 10 men, Nublense doubled their lead early in the second half through Jonathan Cisternas, and held on despite a penalty converted by Mark Gonzalez.
An Andres Vilches brace helped 10-man Huachipato to a 2-2 draw at Cobresal, while Palestino snatched a 1-0 win late over Audax Italiano.
Universidad Concepcion dealt Cobreloa their third straight defeat, courtesy of a 2-0 road win, while Barnechea got their first points of the campaign as they downed San Marcos 1-0.