Argentina's Sergio Aguero scored on a soaring volley in the 76th minute to salvage a 1-1 draw against Bolivia in Friday's opening match of the Copa America.
Bolivia's Edvialdo Rojas stunned Argentine fans with a goal in the 48th minute to give the underdogs the early lead in a match played in freezing winter temperatures. From a corner, Rojas deflected a shot from close range that slipped between the near post and the hands of Argentina goalkeeper Sergio Romero.
Aguero scored six minutes after coming off the bench, ripping a shot into the far corner.
"This makes us sad because we did not achieve our objective, which was to win," Argentina's Lionel Messi said. "We did things well, but we have to improve."
It was a stuttering start for coach Sergio Batista and host nation Argentina, which was out-hustled for much of the Group A match, and did little to justify its tag as joint favorite for the South American championship, along with Brazil.
The hosts dominated the first 10 minutes, but after that Bolivia began out-working the Argentines at midfield and winning more possession.
"The referee let them get away with some things," forward Carlos Tevez said. "But we can't blame him. We did not play well."
Aguero added that "it was difficult and we have to be more relaxed and correct some things. They complicated things defending like they were."
Messi, regarded by many as the world's best player, again failed to translate his stunning club form with Barcelona onto the international stage. He seldom threatened to score or set up goals.
"I don't want to play like Barcelona, that is very difficult," Batista said.
Tevez, the other top forward, was also taken out of the match by Bolivia's hustling defense.
"This will push us to keep improving," Rojas said. "Our work has just begun and we are going to get better. This will serve psychologically to help us with the goals we have, to keep getting good results."
For most of the match Argentina played as individuals rather than a team despite training together for several weeks. But the Gauchos did have a brief spurt of strong play during the first half.
In the 31st, Messi won a loose ball in midfied and passed to Tevez who shot just wide of the near post. Two minutes later Esteban Cambiasso charged in on a loose ball and almost chipped it home.
The opening draw is unlikely to prove too costly for Argentina because eight of the 12 teams will progress to the quarterfinals, meaning only the last-placed team in each of the three groups are sure to miss out.
Argentina, which has won two World Cups, is trying to win its first major event since taking the Copa America in 1993.
Bolivia - a nation that usually vies with Venezuela to avoid last place in South American competition - slowly took the play away from Argentina, winning more loose balls and showing more grit that the favored hosts and deservedly took the lead.
The surprise result evoked memories of the match two years ago when Argentina, under coach Diego Maradona, was hammered 6-1 by Bolivia in a World Cup qualifier played at 3,500 meters (11,500 feet) altitude in Bolivia.
Aguero's equalizer gave Argentina all the momentum in the final 15 minutes, but again Argentina failed to fashion the required teamwork to break down the stubborn Bolivia defense, with Messi and Tevez resorting to individual efforts to try to win the game.
Argentina will face Colombia on Wednesday in its second group game, while Bolivia will take on Costa Rica the following day.
Brazil, which has won four of the past five titles, opens its campaign Sunday against Venezuela in Group B.