SAO PAULO (AP) " Argentina was the runner-up in the last World Cup. This time it's under rising pressure just to qualify.
That pressure will be felt even more in its match Tuesday against Bolivia in the thin air of La Paz, which is located in the Andes at 3,650 meters (11,900 feet) altitude.
Argentina has not won a match there since 2005, upping the stakes a bit more.
Meanwhile, South American rival Brazil will gear up for possible early qualification if it beats Paraguay in Sao Paulo. To advance, the South American group leader needs a victory and a few other results to fall its way. But win or lose, Brazil is heading for the World Cup in Russia with five rounds of qualifying remaining.
Argentina cannot be so confident.
Second-placed Uruguay faces a winnable match at lowly Peru, and fourth-placed Colombia has a real test at fifth-placed Ecuador. Sixth-placed Chile welcomes last-placed Venezuela in Santiago, hoping to climb back into qualifying position.
With five rounds to go, Brazil has 30 points " more than enough to secure a spot in previous World Cups.
Uruguay has 23 and Argentina 22.
With Brazil almost sure to advance " and Venezuela, Bolivia and Peru struggling at the bottom " that leaves six teams fighting for the three remaining automatic spots for Russia. Another South American team could also advance in a playoff.
Argentina put on a poor performance on Thursday, but managed to beat Chile 1-0 in Buenos Aires after a controversial penalty was conceded and converted by Barcelona star Lionel Messi.
The visitors will miss suspended Barcelona midfielder Javier Mascherano, which is making coach Edgardo Bauza think of dramatic changes to the team.
Before the win against Chile and the loss of Mascherano, Bauza was considering a defensive 5-4-1 formation in La Paz, hoping to save his players' energy and capitalize on the ball-holding Mascherano. Now he may be forced into a more offensive formation that relies less on counterattacking.
Bolivian coach Mauricio Soria, who spared some of his main players in the 1-0 defeat at Colombia on Thursday, said his team will not be intimidated by the Argentine stars and should push hard against them. His team will be rested and in familiar surroundings.
"We hope we can make them feel a lot of their fears," Soria said.
After the impressive thrashing of Uruguay 4-1 in Montevideo, Brazil is so close to the World Cup spot that many players are already looking for new challenges as Brazil chases it sixth World Cup title.
For the spot to be assured, Brazil needs to beat Paraguay and see Venezuela overcome Chile in Santiago. Also, Colombia needs to get its first win at Ecuador in 20 years.
Even if the "official" qualification doesn't come, there will surely be a party at Arena Corinthians in Sao Paulo.
Coach Tite, who has won seven straight games in qualifiers since he took over in September, had his best days at Corinthians. He won two Brazilian championships, one Copa Libertadores, and the 2012 FIFA Club World Cup title after a 1-0 victory over England's Chelsea in Japan.
Defender Fagner, also a Corinthians player, will replace suspended Dani Alves.
"I feel no pressure, I want to enjoy every moment of this," Fagner told reporters.
If he doesn't do well, Tite has already brought Sevilla's Mariano for a test.
The Colombia vs. Ecuador match could be key to the aspirations of both teams: Colombia has 21 points, and Ecuador has 20.
The disappointing performance in the 1-0 victory over Bolivia on Thursday is making Colombia fans worry that their team might not qualify for the World Cup. The game in Quito promises to be even more complicated now that coach Jose Pekerman's side has lost its best striker to injury. Luis Muriel had a right-leg injury and will likely be replaced by Miguel Borja or Carlos Bacca.
History does not favor Colombia: it has been 20 years since Colombia last beat Ecuador at the Atahualpa stadium.
Ecuador also has problems for the key clash. Striker Miller Bolanos and midfielder Christian Noboa will be out and their replacements are not yet set.
This story has been automatically published from the Associated Press wire which uses US spellings