Believe it or not, Lionel Messi still has something to prove in his native Argentina - demonstrating that he's the world's greatest player when wearing the famous blue-and-white shirt.

He's not even the country's best-loved player but Messi can start romancing the crowds when Argentina opens the 3½-week Copa America - the South American championship - against Bolivia on Friday.

Messi has rarely managed to replicate his Barcelona form with Argentina - and never when it counts. He didn't score a single goal at last year's World Cup as Argentina was bundled out in the quarterfinals in a humiliating 4-0 loss to Germany.

Everything is now set for Messi to excel when it counts.

An elite power without much recent success, Argentina is the host. Messi is coming off his greatest season at Barcelona, and new coach Sergio Batista has his players trying to mimic the Catalan team's style of quick passes and dominant levels of possession.

"Messi is going to have a great Copa America," Batista said. "Having the best player in the world means a lot, and we'll try to make him comfortable so he produces his best. This is an enormous advantage."

Messi is an outsider at home. He left Argentina for Barcelona as a youth player, spent his formative years in Spain and has never played for one of his country's famed clubs.

His shy personality also leaves many Argentines cold. He seldom jokes around, seems uncomfortable speaking and lacks the charisma of Diego Maradona. Known in Spanish as "La Pulga" (The Flea), Messi has yet to lift a trophy for his country of birth.

"It's been a while since Argentina has won an important title," Messi said. "We need some joy for ourselves and our fans."

Carlos Tevez is likely to be the other main scoring threat for Argentina. Known affectionately as "Carlitos," he's the country's most popular player and is the opposite of Messi. Tevez starred for Boca Juniors, grew up poor in a Buenos Aires shantytown and never stops smiling.

Argentine football could use a lift.

The country's last major international title was in 1993, the Copa America. The last of its two World Cup titles was in 1986, and its club scene is a mess.

River Plate, which has won more league titles than anyone, was relegated to the second division last week, sparking riots between hooligans and 2,200 police. The area around River Plate's Monumental stadium - where the Copa America final will be played July 24 - turned into a smoldering war zone and was closed for several days while a local prosecutor opened an investigation.

The club said this week it has begun making repairs after hooligans ransacked concession areas, ripped out seats and smashed fixtures in toilets.

"The way the stadium was left was shocking," prosecutor Gustavo Galante said.

On the pitch, Brazil is still Argentina's biggest worry.

The Brazilians have defeated Argentina in the past two Copa America finals, and have won four of the last five titles. Argentina is a slight favourite this time, adding even more pressure.

Brazil, which was also knocked out of the World Cup in the quarterfinals, is missing Kaka, Luis Fabiano, Ronaldinho and Adriano. This team is rebuilding and will be led by youngsters such as Neymar, Alexandre Pato, Lucas and Paulo Henrique Ganso.

"These players need to be ready for the 2014 World Cup and playing in the Copa America will be extremely important to give them some much-needed experience," coach Mano Menezes said. "A good result will be important and we want to win the tournament, but I think one of the priorities for us with these young players will be to gain experience."

Argentina and Brazil seem certain to advance from the group stage, and the real action will start in the quarterfinals of July 16 and 17.

Uruguay, Chile, Paraguay and Colombia are considered long-shots, with Ecuador, Bolivia, Peru and Venezuela given little chance.

Also included are Mexico and Costa Rica, which are playing as invited teams to increase the field to 12. Both have arrived with youth teams instead of the senior sides that played in the recent Gold Cup. Mexico defeated the United States 4-2 in that final of that regional championship.

Costa Rica replaced Japan, which bowed out after the March 11 earthquake and tsunami.

Mexican officials suspended eight players from their Copa America squad on Tuesday, banned for breaking training rules after a friendly on Saturday in Ecuador. Mexican federation officials have not disclosed details, but widespread reports say the players had female guests in their rooms.