Two points off top heading into the weekend, Boyaca Chico twice coughed up a lead to draw 2-2 at Atletico Nacional.
Francisco Rodriguez and Juan Perez had put Boyaca Chico ahead in the eighth and 60th minutes respectively, but equalisers from Elkin Calle and Sherman Cardenas helped salvage a point for Atletico.
Deportivo Cali are clear top on 17 points, one ahead of Medellin, after a 1-0 road win over Aguilas Doradas.
Juan Cabezas' goal three minutes out from half-time was enough for Cali, who won their fifth game of the season.
Medellin joined Cali with four straight wins, as they downed Fortaleza 3-2 away from home.
An Alfredo Morelos winner in injury time handed Medellin the three points, as they prolonged their winning form.
Once Caldas sit third, but took two late goals to get past Envigado 2-1.
Envigado led 1-0 after 83 minutes, but a red card to Andres Orozco was followed by a brace to Johan Arango to snap Once Caldas' winless streak of four matches in dramatic fashion.
Fourth are Santa Fe, who rode a Wilder Medina brace to a 5-0 drubbing of Deportes Tolima.
Patriotas Boyaca made it three wins in succession, Marco Lazaga's 14th-minute goal the difference as they beat Uniautonoma 1-0.
Dairon Asprilla's goal powered Alianza Petrolera to a 1-0 win at Junior, Alianza now unbeaten in seven league games.
Cellar-dwellers La Equidad got their first point of the campaign, drawing away to Deportivo Pasto 0-0.
Atletico Huila earned just their second win of the season, edging Millonarios 1-0 via an early penalty converted by Juan Caicedo.
