Argentina failed to seal a place in the 2014 World Cup after being held by Ecuador, while Uruguay and Colombia picked up vital wins in their respective qualifying games.
The United States moved to the top of the CONCACAF group with a comfortable 2-0 win over Panama.
Jozy Altidore continued his good recent form for his country, scoring the opening goal in the 36th minute. Michael Bradley played in Fabian Johnson, who in turn found Altidore for a simple tap-in.
Eddie Johnson then made the game safe in the 53rd minute with a cool finish off an assist from Geoff Cameron.
Coach Jurgen Klinsmann, who has been under pressure over the last couple of months, can now breathe a sigh of relief with the U.S. leading the group with ten points from five games, two ahead of Costa Rica, who only managed a 0-0 draw with Mexico, as the latter's goalscoring woes continued.
Mexico are third on eight points, but have played a game more than Costa Rica and U.S.
In the South American group, a win at the Olympic Stadium in Quito, 2,800 meters above sea level, would have confirmed qualification for Argentina, but Lionel Messi and co. were made to wait for another game at least by an impressive Ecuador side, who thrive in their home conditions.
"We knew it was going to be our hardest game," Sabella said. "We had a lot of things against us -- injuries, suspensions. But the team responded with great dedication. I am very satisfied.
"We're not qualified until it's mathematically certain."
Messi, still struggling for fitness because of an injury, was again left on the bench by Alejandro Sabella, but it did not seem to matter too much as Sergio Aguero gave the Argentines a 1-0 lead in the fourth minute.
Ecuador goalkeeper Alexander Dominguez spilled an effort from Angel Di Maria, and then brought down Rodrigo Palacio, who was looking to latch onto the rebound. Aguero stepped up to take the spotkick and made no mistake.
However, the lead did not last too long as Ecuador levelled things up on 17 minutes, with Segundo Castillo firing home a powerful header off a Walter Ayovi freekick.
Ecuador were the better side in the rest of the game, with Messi's introduction in the final half hour failing to do the trick.
The game was unfortunately marred in the closing stages, with Javier Mascherano kicking at a medic, who was stretchering him off the field, and earning himself a red card. The incident sparked a touchline melee between the two sides, but the score on the pitch remained 1-1.
"We had what it takes to win the game, but we are getting used to draws," Messi told Channel 7. "We failed to take profit from free space in the first half, but we are close to the qualification. That is what matters.
"We scored the first goal very quickly. To play here is very tough. Then they equalised."
Colombia also inched closer to qualification with a 2-0 win over Peru, thanks to strikes from Radamel Falcao and Teofilo Gutierrez.
The Colombians, with a game in hand, are only three points behind leaders Argentina, who have 26 points from 13 matches.
Uruguay, in deep trouble and in serious danger of missing out on the 2014 World Cup, picked up a crucial 1-0 win over Venezuela, courtesy a 28th minute strike from Edinson Cavani, who stepped up admirably in the absence of the suspended Luis Suarez. Chile, though, strengthened their hold on fourth with a 3-1 win over Bolivia.
Four teams in the South American group qualify automatically for Brazil, while the fifth place team goes into a playoff, which is where Uruguay currently stand.
