Tournaments are like time sped up. In the intensity of a few short days, teams can go through changes that might take years under normal circumstances. Think of Brazil in last year's World Cup, for example: They went into the competition on a run of nine straight victories, only to unravel under the pressure of playing at home.
The reverse can also happen. A team can suddenly come together during the course of the tournament and end up doing things it never believed possible before a ball had been kicked. Perhaps Paraguay in the 2015 Copa America are an example of this phenomenon.
Expectations were not high for the team going into the tournament. After reaching the final of the past Copa four years ago without winning a single game, Paraguay slumped to finish bottom of the table in the 2014 World Cup qualifiers. The appointment of Ramon Diaz as national team coach didn't inspire much short-term confidence, either; nothing against the Argentine, but there was a glaring contrast between him and the compatriot who preceded him.
Gerardo Martino, now in charge of his native Argentina, had a successful spell in charge of Paraguay from 2007 to 2011, and he had done some impressive work in Paraguayan football at Libertad and Cerro Porteno prior to taking over. Diaz had no such connection. How could he come in from the cold and sort the side out in time for the Copa? He only had three warm-up matches: two in March and one at the start of June. None of them made big news, especially the last, a scratchy 2-2 draw at home to Honduras.
All those worries appeared entirely confirmed by an awful first 45 minutes in the opening game against Argentina. Paraguay were two goals down and in danger of falling to a landslide, but adversity forced a shake up. Forced to come out and play, Paraguay rode their luck a little and hit back to equalise, which gave them the belief that has underlined their subsequent progress. Paraguay are not the same team that first took the field June 13.
The biggest development has come with the defence. Diaz drilled his rearguard before the quarterfinal against Brazil, and under pressure, the results were plain to see. Paraguay neutralised Brazil's counterattack by squeezing the play and not allowing opponents to pick up speed. This is a Paraguay side that looks set to defend much better against Argentina than they did in that first meeting, when they conceded two but could have conceded 20.
But the Argentine threat is different than the one posed by Brazil; it is more complex and less predictable. Brazil fell into a trap because of their obsession with verticality and a straight line of counterattack. Argentina have a wider range of options.
Of course, there is that attacking trident of Lionel Messi, Angel Di Maria and Sergio Aguero, all looking fresher and sharper than they did at last year's World Cup. But Argentina also boast also Javier Pastore. Coach Gerardo Martino understands Messi has decoy value and can be used to drag the opposing defence around and open up holes; the idea is Pastore can take advantage of such spaces. Against Colombia, it was noticeable that midfielder Lucas Biglia was drifting forward into dangerous positions as an element of surprise.
In that game, Argentina produced one of the finest moments of collective football of the tournament. Javier Mascherano played one of his inch-perfect, long-range diagonal passes out to the right, where Pastore collected and squared low across the face of the goal. A sudden burst of acceleration carried Aguero ahead of his marker for a low finish that was just blocked by the legs of Colombia keeper David Ospina, who reacted superbly to save a follow-up header from Messi, who read the trajectory of the looping ball.
It was a magnificent piece of play, but it didn't result in a goal. This has been the story of Argentina's tournament. For all their attacking ambition (and a balance that can leave them vulnerable down the flanks), they have scored just four times in four games. Perhaps they are saving goals for the decisive stages of the tournament.
But they have been warned. If Argentina cannot find the knockout blow, Paraguay will keep jabbing away until the final whistle.