Argentina stayed top of the South American World Cup qualifying table after being held to a goalless draw by Colombia in a match which saw both sides reduced to 10 men.
With Barcelona star Lionel Messi on the bench, Alejandro Sabella's team were aiming to move one step closer to Brazil 2014, but neither side could make a breakthrough and the key talking point came when Gonzalo Higuain and Cristian Zapata were dismissed in the first half.
Argentina enjoyed the better of the opening exchanges and were close to breaking the deadlock when visiting goalkeeper David Ospina saved Higuain's volley from inside the six-yard box and defender Marcos Rojo headed the rebound against the crossbar.
Close to the half-hour mark, both sides were reduced to 10 men when Higuain and Colombia defender Zapata saw red for getting into a scuffle.
Argentina introduced Messi in the 57th minute but even he could not find a way past Ospina.
When they did have the ball in the net following good work from Sergio Aguero, the referee disallowed it for an offside against Messi.
"It is not a fair result," said Messi. "We deserved to win. I was not interfering with play on the goal that the referee disallowed by Kun Aguero. I believe we were superior and only the referee's mistake and the goalkeeper's performance stopped us from winning."
Colombia defender Mario Yepes said: "The match dynamic changed when the two players were sent off. We came here to win, but a draw under these circumstances is not a bad result at all. I think we took an important step in our objective to reach the Brazil World Cup."
Argentina top the qualifying group with 25 points after 12 matches, five clear of second-placed Colombia.
Elsewhere, Chile moved into the fourth qualifying spot with a 2-1 win over bottom-placed Paraguay.
Gremio forward Eduardo Vargas opened the scoring for the visitors shortly before half-time and Arturo Vidal doubled Chile's lead after the break.
Paraguay peppered the Chile goal but were unable to find a breakthrough until Roque Santa Cruz struck with three minutes on the clock. It proved too little too late as Paraguay's World Cup hopes were dealt another blow.
Venezuela missed the chance to gain further ground on sixth-placed Uruguay as they were held to a 1-1 draw in Bolivia.
Venezuela maintain fifth spot, although Uruguay have a game in hand, while Bolivia remain second from the bottom.
Juan Arango gave La Vinotinto a 1-0 lead in the 58th minute and it looked to be enough for the visitors until Jhasmani Campos scored a late equaliser to secure a point for Bolivia.
In the group's other match, Claudio Pizarro's 11th minute strike was enough to seal a 1-0 win for Peru over Ecuador.
Peru moved within four points of fourth-placed Chile and have a game in hand, while Ecuador could have jumped into second.
Information from the Press Association was used in this report