Alejandro Sabella searches for balance
Argentina's new coach needs to resolve old problems ahead of World Cup qualifying matches against Bolivia at home on Friday and Colombia away four days later.
Blending a fearsome attack including Barcelona star Lionel Messi with a shaky defense proved beyond coach Alejandro Sabella's predecessors Sergio Batista and Diego Maradona.
Sabella must fix the inconsistencies quickly after his first two qualifiers in charge resulted in a promising 4-1 win against Chile - which included Messi's first competitive goal in 17 international matches - followed by a first ever loss at Venezuela.
Sabella said he learned valuable lessons from the Venezuela defeat.
''I should have made a substitution after five minutes of the second half because they finished the first half better,'' he acknowledged. ''And we didn't travel a day before like we will do against Colombia.''
Anything but victory against underdog Bolivia would put Argentina's campaign under mounting pressure, but Manchester City striker Sergio Aguero said nothing could be taken for granted.
''Nowadays, any country can beat you. We have good players and we have to be prepared to start winning all these games,'' he said.
Sabella's principal absentee is Real Madrid winger Angel Di Maria, who damaged his left hamstring during his club's 7-1 rout of Osasuna on Sunday.
Di Maria was in sparkling form before his injury and his loss will be a blow as Sabella studies ways of breaking down a Bolivia side likely to defend in numbers.
''There aren't any secrets,'' acknowledged Bolivia coach Carlos Quintero. ''Our success against Argentina will depend on our defensive play.''
Elsewhere in South America on Friday, early leader Uruguay hosts Chile, Venezuela travels to Colombia and Ecuador visits Paraguay.
Uruguay coach Oscar Tabarez has six regular players ruled out through injury, including talismanic striker Diego Forlan, as he looks to build on a 4-2 home win against Bolivia and 1-1 draw away to Paraguay.
Liverpool's Luis Suarez and Napoli's Edinson Cavani will likely lead the line in Forlan's absence.
Chile's preparations look to have hit problems after local media reported that five players had broken a team curfew and could face sanctions.
Coach Claudio Borghi has made no official comment about the event, but has at least been boosted by the return from injury of Barcelona star Alexis Sanchez.
''Alexis is an elite player, like some of the players we have,'' Tabarez said. ''Generally, the great players have an influence over how the team plays.''
Meanwhile, Colombia will hope to follow up a 2-1 opening win at Bolivia with victory at home to Venezuela in a match between two teams that failed to qualify for the 2010 World Cup.
As the game against Argentina showed, however, Venezuela is no longer the continent's pushover and has Malaga forward Salomon Rondon providing pace and penetration up front.
Venezuela is still the only CONMEBOL team never to reach the finals, but with Brazil qualified automatically as host, there is an extra spot available for South American teams.
In the final match in the region, Paraguay should have Borussia Dortmund striker Lucas Barrios fit to return after three months out with an injury sustained in the Copa America.
Barrios' recovery is well timed, as fellow forwards Roque Santa Cruz of Real Betis and Oscar Cardozo of Benfica were left out of the squad with injuries.