Argentina were below-par all evening and finally slumped to a 2-0 defeat against Ecuador in Buenos Aires, as the absences of Lionel Messi and Sergio Aguero were felt keenly up-front. 

Captain Messi was out of the reckoning and El Kun managed just 20 minutes before limping off the field, after having the nation's best chance of the evening. 

Without them the Albiceleste appeared out of ideas in attack and dangerously shaky at the back, and Ecuador's first World Cup qualifying victory on Argentine soil was more than deserved. 

Ecuador started brightly and had a great chance to take the lead in the 10th minute.

Antonio Valencia broke into space just outside the box, but his delivery across the penalty box to pick out the unmarked Jefferson Montero was overhit.

At the other end, Argentina went close but not close enough in the 17th minute.

Alexander Dominguez was forced into a save by Angel Correa and the former then produced a finger-tip save to deny Aguero from close range after Angel Di Maria teed up his team-mate.

That proved to be Aguero's last bit of action as he was carted from the field two minutes later.

Aguero clutched at his left hamstring and signalled to the bench after chasing down Achilier.

Ecuador continued to be a threat on the counter-attack in the first half, though they spurned another opportunity to hit the front approaching the half-hour mark, when Miller Bolanos fired over from the edge of the area following Valencia's cutback.

It was more of the same after the interval, Ecuador wasting yet another chance to break the deadlock in the 58th minute.

Lucas Biglia slipped in the middle of the field and Christian Noboa pounced and found himself in space outside the box but his chipped effort sailed wide of the post.

Argentina had opportunities in quick succession from the 67th minute, though neither Javier Mascherano nor Di Maria found the back of the net.

Mascherano linked up with Tevez inside the area but the outstretched Barcelona midfielder was unable to guide the pall beyond Dominguez, while Di Maria's attempted chip was dealt with.

Argentina were then made to pay as a flick on from Segundo Castillo fell to Erazo, who stooped low to head past Romero with nine minutes remaining.

And it got better for Ecuador just seconds later as Valencia sprinted into the box and passed the ball to Caicedo, who made no mistake from close range.

Argentina's forward Angel Di Maria (L) argues with Ecuador's forward Jefferson Montero during their Russia 2018 FIFA World Cup qualifiers match. Photo: AFP