Hector Tapia's league-leading Colo Colo side gave up a lead in a surprise 2-1 loss at home to Universidad Concepcion on Sunday.But they still remain seven points clear at the top after Catolica were beaten at Cobreloa in another shock on Saturday.
At the Estadio Monumental David Arellano, Colo Colo looked on track for victory when Esteban Paredes struck his 11th league goal of the campaign.
It took until first-half stoppage time but Paredes delivered with a 30-yard free-kick, which went over the defensive wall and in off the post.
A fluent counter-attack by the visitors led to Pedro Munoz equalising on 54 minutes as he completed the pitch-long move with a neat finish in a one-on-one with Justo Villar.
Seventh-placed Concepcion took the lead in the 68th minute when Leonardo Monje powered a strike under Villar from the edge of the area.
Substitute Sebastian Toro struck the crossbar for Colo Colo soon after with a thunderous 30-yard effort that had Cristian Munoz beaten but that was as close as the home side came to an equaliser.
Making matters worse for the hosts, Paredes was sent off in additional time after picking up two yellow cards in a matter of seconds for remonstrating with the referee, believing he should have been awarded a late penalty.
Universidad Catolica remain second despite back-to-back league losses, the latest a 2-1 defeat at Cobreloa.
Jose Perez and Gustavo Cristaldo struck for the hosts before Milovan Mirosevic was sent off for Catolica, who pulled a late goal back through Tomas Costa but were unable to find an equaliser.
O'Higgins moved level on points with Catolica after a come-from-behind 3-2 win over a Cobresal side who finished their encounter with eight men.
Ever Cantero's early brace had Cobresal ahead away from home but the clash was level by half-time as Pablo Hernandez and Diego Chaves – with a penalty – scored.
Carlos Herrera picked up a second yellow card early in the second half and Osman Huerta put O'Higgins ahead soon after.
Mariano Torres was also booked a second time soon after for an off-the-ball challenge before Cantero saw red for a reckless tackle on halfway.
Elsewhere, Nublense thrashed Deportivo Iquique 3-0, Palestino and Rangers drew 0-0 and Union La Calera upset Universidad Chile 1-0.
Santiago Wanderers crushed Union Espanola 4-0, Huachipato eased past Antofagasta 4-1 and strugglers Everton and Audax Italiano drew 1-1.
