Argentina's dream of a first major title in 22 years was given a reality check on Saturday when Paraguay came from behind to snatch a last-gasp 2-2 draw in a Copa America classic.

English Premier league star Sergio Aguero and captain Lionel Messi looked to have put Argentina on the road to a routine victory in Group B after firing the tournament favorite into a 2-0 first-half lead.

But a long-range strike from Nelson Valdez hauled Paraguay back into the contest before Argentine-born forward Lucas Barrios grabbed a dramatic equalizer in the 90th minute.

The stunning comeback left Argentina in shock and could complicate its route through the knockout rounds in Chile.

"It is a sin to give away an equalizer in the final minute," Argentina coach Gerardo Martino said afterward, lam-basting his team's "neglect."

"We lost control and the other team had four or five chances to get a draw.

"We had many chances to win. I do not think we need to change anything. What we have to look back on is the two different games we played in the 90 minutes today."

Paraguay scoring hero Barrios was jubilant after his team's heroics.

"This group is so tough that getting a draw in the last minute against Argentina is like a victory," said Barrios, who plays for Montpellier in France.

Paraguay's other scorer, Valdez, paid tribute to the spirit shown by his teammates.

"Individually we are less than Argentina, but as a team we are better than them," he said. "We needed a slap in the face at halftime."

Argentina, runner-up in the World Cup final last year, is aiming to win its first major tournament since victory in the 1993 Copa America.

It now faces a crucial second match on Tuesday against holder Uruguay, which struggled to impress in a lackluster 1-0 win over lightweight Jamaica earlier Saturday.

Uruguay, the defending champion, badly missed suspended striker Luis Suarez, who is still serving a ban for biting Italy's Giorgio Chiellini at the World Cup.

La Celeste captain Diego Godin demanded improvement on Saturday after a solitary goal from Cristian Rodriguez saved face against the Jamaicans.

Improvement demanded

"It's a good result to start with; now we need to correct some mistakes," Godin told Chilean television.

"It's very important to win the first game in the Copa America, as it is in any big tournament," the Atletico Madrid defender added. "We have to go game by game, but we will have to improve and keep working hard."

Uruguay barely created a chance against Jamaica, one of two teams from the North America, Central America and Caribbean zone (CONCACAF) invited to take part in the Copa America, along with Mexico.

Uruguay finally broke the deadlock seven minutes after the break with a cleverly worked set-piece.

Boca Juniors midfielder Nicolas Lodeiro floated a free kick from wide on the left for defender Jose Maria Gimenez, who lost his marker to head back into the area for Rodriguez, on loan with Brazilian side Gremio from Atletico Madrid, to finish.

Sunday's Copa America action sees the entrance of five-time world champion Brazil, which faces Peru in Group C.

Colombia plays Venezuela in the other match on Sunday.