Concepcion - World Cup runners-up Argentina came to the Copa America in Chile as favourites and were expected to put plenty of goals past their opponents.
Instead they are the lowest scoring team to reach the semi-finals in which they clash with Paraguay in the southern city of Concepcion on Tuesday (2330 GMT).
"It's terrible what it's costing me to get a goal," Lionel Messi, accustomed to breaking scoring records in Spain and Europe with Barcelona, said after Argentina beat Colombia 5-4 on penalties following a 0-0 draw in their quarter-final.
Argentina's attacking game is improving with each match but defences at the tournament, especially in their tougher half of the draw, have been hard, putting many men behind the ball to handle the likes of Messi and Sergio Aguero.
Aguero has scored two goals, Gonzalo Higuain one and Messi a penalty in Argentina's four matches. Their defence has three cleans sheets since conceding two goals in a 2-2 draw with Paraguay in their opening match.
"I don't understand, it appears there's a different football in South America," Aguero told reporters after earning a yellow card for dissent protesting at rough treatment from the Colombians and being denied a penalty.
"The referee said 'This is (Latin) America, kids', yet we're from here," the Manchester City striker added, commenting on something Mexican Roberto Garcia Orozco had said in the heat of the match suggesting forwards could not expect the same protection they were used to in Europe.
Messi, who is also carrying a yellow card into the semi-final, Aguero and Brazilian Neymar, suspended after a red card against Colombia in the group stage, have had a tough time trying to break through defences and been victims of systematic fouling to break their rhythm.
Argentina and Paraguay finished in the top two places in Group B with four goals apiece from three matches. Paraguay then added a fifth with a penalty in their 1-1 quarter-final draw with Brazil before going through 4-3 on penalties.
In the other half of the draw hosts Chile, who face Peru on Monday night, are way out in front with 11 goals from four matches.