Ecuador's victory, which included a goal by Manchester United's big summer signing Antonio Valencia, enabled them to move into the fourth and final automatic qualifying spot, as they bid for a third successive place at the FIFA World Cup finals, one point above Argentina.
The one good piece of news for Argentina - whose coach Diego Maradona is increasingly coming under pressure despite his legendary status as a player - was that Uruguay beat Colombia 3-1 in Montevideo. Had Colombia won, they too would have moved above Argentina, but they were unable to gain their first away win of the series and Uruguay prevailed after a run of four matches without a win.
In a fiery encounter, both sides had one player sent-off, Uruguay's Carlos Valdes in the 30th minute when they were leading 1-0 and then the visitors were reduced to ten men when striker Teofilio Gutierrez was shown red for deliberate handball at the start of the second-half.
Uruguay wrapped up victory in the 88th minute largely thanks to the persistence of Atletico Madrid talent Diego Forlan, as he chased what seemed a lost cause when a shot was deflected and was heading out.
However, the veteran striker got to the ball and cut it back inside for Sebastian Eguren to rifle the ball home and rub salt into Colombia's wounds as his goal was the winner against the same opponents earlier in the campaign in what remains the Uruguayan's sole away victory.
Uruguay's win enables them to climb above Colombia into sixth, a point behind Argentina.