Uruguay: Penarol punish eight-man Tacuarembo
A defender was taken to hospital with concussion and a goalkeeper suffered suspected knee cartilage damage in Universidad de Chile's 3-3 draw with Santiago Wanderers.
Frustration got the better of Tacuarembo who had three players sent off late in their 3-1 loss to Clausura championship leaders Penarol.
Penarol, who have taken a maximum 12 points from their four matches, had already settled the result when midfielder Claudio Innella was shown a red card for a violent foul and defenders Carlos Dutra and Jose da Silva were dismissed for second bookings.
Striker Antonio Pacheco scored twice in the first half to take his tally to six. He had to take a 32nd-minute penalty twice because goalkeeper Jonny da Silva, who saved it, was ruled to have moved early. Substitute Diego Alonso scored their third in the 78th.
Jorge Ramirez scored a first-half hat-trick including two penalties as Central Espanol upset Defensor Sporting 4-3 away.
Striker Sergio Blanco scored six minutes from the start and six from the end to give champions Nacional a 2-0 win over Liverpool that leaves them five points off the pace.
Chile's two most popular clubs, Colo Colo and Universidad de Chile, were held to draws in the Apertura championship.
Moises Villarroel volleyed a brilliant 83rd-minute equaliser from 30 metres to give Santiago Wanderers a 3-3 draw with Universidad de Chile, who had led 3-1 with 19 minutes to go.
Wanderers defender Agustin Parra was concussed in a collision with his own goalkeeper David Reyes after 17 minutes and had to be taken to hospital.
Universidad's keeper Miguel Pinto, likely to get a place in Chile's World Cup squad and just back from injury, suffered a twinge in a knee cartilage and did not reappear for the second half. He was due to have tests on Monday to see if he needed surgery.
Colo Colo needed an equaliser from Paraguayan forward Cristian Bogado eight minutes from time to salvage a 2-2 draw at home against Nublense.
Union Espanola lead with 11 points from five matches after a 2-1 away win over Huachipato.
Promoted Sport Colombia scored twice in the last four minutes to upset title holders Nacional 2-1 away in the Apertura championship.
Cerro Porteno, winners of last year's Apertura, beat Trinidense 2-1 away to go top with a maximum nine points.
Match official Cesar Franco was shot in the leg as he was mugged close to his home last week and was unable to take his position as linesman in the match between Tacuary and Libertad, he told the radio programme Penalty Spot.
Roberto Gamarra scored twice in Libertad's 4-0 win.
America ended a run of 11 matches without victory by beating champions Independiente Medellin 1-0 with an own goal by defender Leiton Jimenez in the 83rd minute. Midfielder Mahler Moreno missed a penalty for Medellin in the 70th.
Real Cartagena lead with a maximum nine points from three matches after recovering from a goal down to beat Atletico Huila 2-1 at home.
Ailing Bogota giants Millonarios were held 0-0 at home in El Campin stadium by modest Deportes Quindio and fans called for the head of their coach Luis Augusto "Chiqui" Garcia.
Champions Universitario and Alianza Lima, the team they beat in the 2009 championship final, lost on the opening day of the new season fielding a majority of reserves as they prepared for mid-week Libertadores Cup matches.
Universitario lost 2-1 at home to Inti Gas while nine-man Alianza, who are at home to South American champions Estudiantes of Argentina on Thursday, went down 1-0 away to a stoppage time goal by promoted Leon de Huanuco.
Alianza had Colombian forward Johnnier Montano sent off after 37 minutes for dissent after an initial booking and midfielder Juan Jayo was dismissed in the 66th for a second bookable foul.
Argentine midfielder Gustavo Rodas scored the winner one minute into stoppage time.
El Nacional beat champions Deportivo Quito 3-1 away at the Atahualpa in the capital to leave them still looking for their first points after two matches.
Barcelona beat Macara 2-0 at home in Guayaquil to top the standings with a maximum six points.
Deportivo Italia, who did not play at the weekend due to their Libertadores Cup match away to Colo Colo in Chile on Tuesday, are top of the Clausura championship with 10 points from four matches.
Real Esppor, who beat Yaracuyanos 3-1 away, are second a point behind.