Argentina spent almost the entire 90 minutes on the back foot, but Sergio Aguero's penalty in the fourth minute was sufficient for the side to hold on and take a road draw.
Sergio Aguero's early penalty was cancelled out by Segundo Castillo's header, and despite frantic home pressure the Albiceleste showed just enough to earn one point that keeps them on top of the CONMBEOL qualifying table and on track to qualify for Brazil 2014.
Seeking a win that, with help from Tuesday's other results, could confirm its place in the 2014 World Cup, Argentina could not have asked for a better start. Just one minute into the encounter, Angel Di Maria picked up the ball from deep, and, turning onto his left foot, released an effort towards goal. Alexander Dominguez parried straight into the path of Rodrigo Palacio and felled the advancing forward, leaving a penalty as the only option for the referee.
In the absence of Lionel Messi it was Aguero who picked up the ball, and the Manchester City star did not err as he sent Dominguez the wrong way to open the scoring.
Playing in front of a packed Estadio Atahualpa, Ecuador was not discouraged by the early setback. The Tricolor, which maintained its third-place standing with the point, immediately went on the offensive, most notably through Jefferson Montero, who delighted in tormenting Gino Peruzzi with his dribbling skills on the left flank. A run from the winger saw him cut down close to goal, and from the resulting free kick, Castillo met the cross and powered a header past Sergio Romero to restore parity.
Both sides looked for more after the equalizer in a frenetic first 45 minutes. Argentina threatened most consistently from deep, with Dominguez atoning for his earlier mistake with a handful of strong saves to keep out Di Maria and Aguero's long-range bombs. Antonio Valencia, meanwhile, went close at the far post with a header that went over the bar. Despite his and Montero's brilliance out wide, though, Ecuador could not take advantage and notch a second goal, going into the break tied.
Buoyed by that positive first-half showing, Ecuador immediately went on the front foot after the interval, stretching the Albiceleste this time down the right flank through Valencia. The Manchester United star almost played in Joao Rojas in the opening exchanges, but Sergio Romero was attentive to turn a cross-shot behind with his defense in tatters.
Felipe Caicedo had been busy throughout the game without really threatening Romero's goal, but less than 10 minutes into the half the striker was incensed at being denied a penalty. Jose Basanta was defeated in the box with a silky flick over his head, but Caicedo was already tumbling as Romero came out to cover the ball, and despite his fervent protests referee Enrique Caceres was right to continue play.
The Argentine faithful in the crowd were briefly lifted with the entrance of Lionel Messi on the hour, but with the away team playing with men behind the ball, opportunities were limited for the captain to work his magic. Ecuador continued to set the pace and went close once more from a set piece when Frickson Erazo headed over.
In spite of all the home pressure, Argentina could have stolen all three points in the last 15 minutes. Di Maria defied fatigue to embark on a storming run down the left, but with Messi waiting in the middle released a feeble cross-shot that was far from either his teammate or the net. It was a rare moment of danger for the visitors, who saw Javier Mascherano sent off in bizarre circumstances for lashing out at a pitchside official, as they finished the game holding on for a point.
The draw means the Albiceleste remain in first place, but Colombia's victory over Peru means the deficit at the top is cut to two points. Ecuador, meanwhile, stay in third, and could be caught by Chile should the Roja defeat Bolivia later in the evening.