It could get even uglier if Argentina loses to Uruguay on Saturday in a quarterfinal being played in the northern city of Santa Fe, the same venue as last week's debacle and just a short drive from Messi's birthplace in Rosario.
This is supposed to be the tournament Argentina wins to end an 18-year drought without a major international title. But its small neighbor across the River Plate estuary stands in the way with almost the same team that reached last year's World Cup semifinals.
"Against Uruguay, this is a final," said Messi, who has not scored for Argentina in his last 15 competitive internationals, including the Copa America, World Cup and World Cup qualifiers.
The other three weekend quarterfinals offer more regional intrigue. Colombia faces Peru on Saturday, before two-time defending champion Brazil plays Paraguay and Venezuela takes on Chile on Sunday.
The final is July 24, and that's the first time Argentina and Brazil could meet.
Brazil has won the last two titles — both in finals against Argentina — and four of the last five.
Messi and Argentina redeemed themselves on Monday, defeating Costa Rica 3-0. After two miserable opening games, coach Sergio Batista dropped Messi back into a playmaker role. He dribbled and turned just as he does at Barcelona, threading passes to forward Sergio Aguero, Gonzalo Higuain and Angel Di Maria.
Batista will go with the same 11 with Fernando Gago and Javier Mascherano at midfield.
The victory still wasn't overly impressive, as Costa Rica fielded an under-23, Olympic-style team in the South American championship, where they played as a guest from the CONCACAF region.
Uruguay, meanwhile, has one of the most experienced teams in the tournament led by forward Diego Forlan and Luis Suarez.
Messi, who has hardly spoken publicly during the first two weeks, held his first news conference on Thursday and was immediately asked if — faced with the nasty insults from fans — he intended to keep playing for Argentina's national team.
"Although they criticize me, I will always come to the national team," Messi said. "Criticism by the fans bothers me and everyone, but we are aware that we didn't do things correctly. ... Nobody likes to be whistled at. It happened because the team did not play well." Julio Grondona, the president of the Argentine Football Association, in a radio interview talked tongue-in-cheek about Messi staying away from Argentina, where he is often seen an outsider and lacks the charisma of Diego Maradona.
"The solution would be if he (Messi) said: 'I'm not coming again, I'm staying in Spain.'" The game could center around two forward who are teammates at Atletico de Madrid — Forlan and Argentina's Sergio Aguero.
Aguero, who has said he "will not return" to the Madrid club, has scored three of Argentina's four goals.
Forlan is in a terrible slump. Voted the best player in last year's World Cup, he has not scored a goal with the national team since South Africa. His last goal with Atletico de Madrid was in March.
Forlan's had chances in the first three games, left open several times only to shoot wide or over the crossbar.
"I'm not going to drive myself crazy. The goals will come," Forlan said.
Uruguay coach Oscar Tabarez said he was not worrying about Messi.
"If you have a problem, and you have no solution — why worry about it," Tabarez said.
