BUENOS AIRES - Colombia's championship was hit by more refereeing problems at the weekend, with the Apertura championship's playoff stage getting off to a stormy start. Six players were sent off in the Peruvian match between Alianza Atletico and Sport Ancash while Nacional beat arch-rivals Penarol 3-2 in Uruguay. COLOMBIA The playoff stage began with refereeing controversy and red cards as Once Caldas beat Boyaca Chico 2-1 with a penalty widely described in media reports as non-existent. Argentine Ariel Carreno went tumbling over in the 76th minute and referee Sebastian Valencia pointed to the spot amid furious Chico protests which earned a red card for defender Ever Palacios plus two members of the Chico bench. Johan Fano fired home his eighth goal of the championship. Caldas had coach Javier Alvarez dismissed for running onto the pitch and Luis Nunez for dissent in the Group A match. At one point Chico players made gestures suggesting they would walk off the pitch while club president Eduardo Pimental later threatened to boycott Wednesday's game against Deportes Tolima "Either they give us better referees or they bring in referees from abroad," he told Caracol radio. Cucuta coach Jorge Luis Pinto was sent off for the third time this year, this time for insulting the fourth official, as his team were held 1-1 at home by Envigado in Group B. Luis Narvaez (Cucuta) and Neider Morantes (Envigado) were also dismissed for fighting in the 85th minute. Envigado coach Oscar Aristizabal said: "There's a refereeing crisis in the game but it's also up to us to keep our heads. ...When does Pinto not complain about the referee?" PERU Alianza Atletico and Sport Ancash dished up an unsavoury encounter in the searing heat of Sullana as they shared six red cards. Ancash's Oswaldo Rivas was first to go for a second bookable offence five minutes before halftime. Carlos Sotelo (Ancash) and Roberto Farfan (Alianza) followed for fighting early in the second half and Frank Vega left Ancash with eight men when he was sent off for a bad tackle. Marcio Valverde (Alianza) was dismissed for elbowing and his team mate Rafael Farfan for a second bookable offence. Alianza Atletico won 2-0. Alianza Lima were knocked off the top of the first stage after losing 3-0 at first division newcomers Inti Gas in Ayacucho. Tempers frayed when Inti Gas defender Renzo Reanos tried some fancy tricks late in the game. He was surrounded by furious opponents at the end and a scuffle broke out in the players tunnel. Juan Aurich went top after drawing 2-2 with Melgar. URUGUAY Gustavo Biscayzacu scored a hat-trick for Nacional while Antonio Pacheco scored both goals for Penarol in a dramatic derby. Biscayzacu struck first in the 14th minute, but Pacheco scored from a free kick and penalty to put Penarol ahead. Biscayzacu replied again before halftime and headed the winner in the 73rd minute. Nacional had Oscar Morales dismissed before controversy erupted in the last minute when Penarol striker Carlos Bueno went down in the area and claimed a penalty. Instead, Bueno was given a second yellow card for diving and sent off but the Penarol striker remained on the touchline and, when the final whistle went, became involved in a scuffle with Nacional players in the centre circle. Defensor Sporting, who knocked Argentina's Boca Juniors out of the Libertadores Cup last week, stayed top of the championship's second stage by thrashing Rampla Juniors 4-1 away. VENEZUELA Caracas FC and Deportivo Italia drew 1-1 in the first leg of the 2008/09 championship's final. Crisitian Casserres headed Deportivo in front from a corner in the 51st minute and Emilio Renteria levelled five minutes later with a 30-metre shot which caught goalkeeper Alan Liebeskind off his guard. PARAGUAY Guatemala striker Carlos Ruiz scored a hat-trick to help Olimpia win 5-3 at Rubio Nu, a result which kept them third in the Apertura championship. Cerro Porteno beat Sol de America 1-0 with a late goal from Julio Irrazabal to stay one point clear of Libertad, who scored four times in 25 minutes after halftime to beat Sportivo Luqueno 4-1. ECUADOR Emelec went top of the championship's first stage when Franco Mendoza scored in the 92nd minute to give them a 1-0 win at Manta. The Electrics went two points clear of previous leaders LDU, who drew 2-2 at Espoli after conceding an 89th minute goal scored by Marquinho.