All eyes on Messi at Copa America climax

The three-week South American football showpiece reaches its climax at the Estadio Nacional with Argentina aiming to win their first title since 1993, 12 months after defeat in last year's World Cup final.

Chile are anxious to shed their unwanted tag as the perennial nearly men of South American football, ending decades of hurt by winning a first Copa America crown after nearly a century of failure.

Argentina captain Messi has declared himself "desperate" to win an international title after winning every honor at club level with Barcelona.

Coach Gerardo Martino said Friday victory for Argentina was almost an "obligation".

"It's very difficult to imagine what would have happened if we had not reached the final," Martino said.

"In reality the expectations this group of players generates are so great that sometimes they think winning is an obligation."

Argentina head into the final in buoyant mood after thrashing Paraguay 6-1 in the semi-finals.

Martino said Argentina's players had been told to take the emotion out of what is expected to be a highly charged occasion.

"There is always an emotional factor in the final, but the guys must ignore that. These are the kinds of games where there is so much tied up in the result that you can sometimes change the way you approach the match.

"But what will bring us the title is to do things as usual."

- Aguero unfazed -

Striker Sergio Aguero insisted that the pressure of ending a 22-year title drought was not getting to Argentina.

"It's true that for many years we have not won anything," Aguero said.

"But we have many players with experience of winning titles, so the pressure is not a problem.

"With the group of players we have, we have got to win a title and we are one step away from doing that."

Since a 6-1 defeat to Argentina in the inaugural South American Championship in 1916, Chile have endured years of frustration.

While Argentina will join Uruguay as the most successful side in the tournament's history if they win their 15th title on Saturday, Chile are still waiting for their first crown after finishing runners-up four times.

Chile have also never beaten Argentina at the Copa America in 24 attempts.

Chile's own golden generation -- featuring the likes of Arturo Vidal, Alexis Sanchez and Claudio Bravo -- believe Saturday represents a now-or-never moment.

- Chile ready to attack -

Coach Jorge Sampaoli said Chile would not abandon their trademark attacking style even against an Argentina team which tore Paraguay to pieces.

"Our preparations have been similar to previous matches. Of course we are taking some things into consideration about our opponents, but our system will not change," Sampaoli said.

"We will try to dominate the game and the game may depend on who dominates who. But the system we have used has given us the opportunity to be where we are now, in the final, and we intend to continue playing the same way."

Sampaoli declined to comment about a plan to combat the threat posed by Argentina's "Fantastic Four" -- Messi, Aguero, Javier Pastore and Angel Di Maria.

"We have spoken to the players about some of our concerns and we have communicated some things that we believe are important to keep in mind so that we have a good game," Sampaoli said.

The final takes place at 5:00 pm (2000 GMT) and will be the only match of the tournament to feature 30 minutes of extra time if the scores are tied after 90 minutes.