Argentina's deficiencies to score pile pressure on Messi and Co.

CONCEPCION, Chile --

Lionel Messi could not believe his luck. Colombia's David Ospina's outrageous save denied the Argentine attacker from a close-range header on Friday, and four full games into the Copa America, the Barcelona forward has only one goal to his name - a penalty against Paraguay in his opening match.

"It's unbelievable the trouble I'm having in scoring with the national team," the 28-year-old lamented after his side overcame Colombia on penalties in the quarterfinals. But it is not just Messi. Despite its fine football, Argentina has netted only four goals in as many games at Chile 2015 -- and that is putting even greater pressure on its captain in this tournament.

Since scoring twice in the first half against Paraguay, the Albiceleste have added just two more goals in 324 minutes of football. Sergio Aguero's header was enough to see Gerardo Martino's men beat Uruguay 1-0, while Gonzalo Higuain's goal edged out Jamaica by the same scoreline and Argentina needed penalties to defeat Colombia following a scoreless game against Jose Pekerman's side in the last eight.

"It is clear we have a problem with our finishing," Martino said at the prematch press conference on Monday ahead of his side's semifinal against Paraguay. "There is a red mark against our finish¡ng and it is something we have to improve on. But I agree with Javier (Mascherano) that it is more of a coincidence than anything else."

Perhaps. But the problem is more than just the finishing. The return of Lazio's Lucas Biglia in midfield for Argentina's second game, against Uruguay, gave Martino's men better balance defensively than with Ever Banega there, but it has also restricted the Albiceleste attack.

"Biglia gives us more balance in midfield," Tata said ahead of the 2-2 draw against Paraguay on June 13. "But Banega gives us more play." With the Lazio midfielder short of full fitness, the Sevilla man started that game and Argentina played probably its best and worst football of the competition in a classic game of two halves in La Serena.

With Biglia back, they look more solid. Goals, however, have been hard to come by with him on the pitch. For all Tata's talk about the importance of style, he has two defensive-minded midfielders in the team in Biglia and Javier Mascherano, while the third (Javier Pastore) is often too far from the opposition area and has been unable to link up effectively with the forwards on the edge of the box.

That has left striker Sergio Aguero isolated, while Angel Di Maria is still struggling to find form for his country in this tournament.

"Before the friendly against Germany last year, I said Di Maria was one of the five best footballers in the world," Martino said on Monday when asked about Angel. "And I maintain that." In truth, however, the Manchester United winger is nowhere near his best.

Di Maria thrives when attacking spaces at speed, but Argentina has faced four defensive rivals so far in this Copa and only against Jamaica did the former Real Madrid winger really impress.

Up against rivals squeezing spaces, Martino is keen for his fullbacks to push forward and help the attack. That, however, is another problem because Marcos Rojo is a converted center back who offers very little offensively and Pablo Zabaleta lacks the pace to really threaten down the right - although he did set up Aguero's goal against Uruguay with an excellent cross.

That strike saw Argentina at its very best. Some superb trickery from Pastore took two defenders out of the equation, Zabaleta then whipped in a pinpoint center and Aguero headed home. And more of that is now needed if Argentina is to go all the way in to the title in Santiago next weekend.

But the deficiencies at fullback and in central midfield (two problem positions even at youth level in Argentine football) mean Messi is not getting the help he needs and the support he receives at club level with Barcelona. The Barca midfield moves the ball around much more quickly than the Argentina trio, with lovely linkup play on the edge of the box from Andres Iniesta, Ivan Rakitic and the now-departed Xavi creating all sorts of problems for their rivals and space for the forwards.

Argentina is missing that, as well as attacking fullbacks like Dani Alves and Jordi Alba who offer an additional threat with their forward runs. The result sees Messi dropping deep to try and influence games and although he has performed exceptionally well in this tournament, he has been unable to influence matches quite like he does for the Catalan club.