Argentina coach Gerardo Martino is concerned about his team's failure to sustain their rhythm for a whole match after a 1-0 win over Uruguay on Tuesday.
Sergio Aguero's second-half header was enough to give Martino's men victory over their close rivals, but there were some nervy moments in the final minutes as Oscar Tabarez's team came close to a late leveller.
Paraguay fought from 2-0 down against Argentina in their opening game, securing a 2-2 draw.
"What I saw basically was 70 minutes similar to the game against Paraguay," Martino told a news conference.
"We had the ball, we tried to create chances, break down Uruguay's scheme, playing between the lines and attacking on the wings. But after that we lost mobility in our passing and therefore we lost the ball.
"It causes us a lot of harm when we don't have control of the match. And if there is one thing to look ouy for it is the fact that we weren't able to maintain our rhythm for 90 minutes in either of the games."
Uruguay forward Diego Rolan missed a glorious chance as he fired over the bar late on, while Argentina had goalkeeper Sergio Romero to thank for an important save right at the end.
Martino was thankful to his shot-stopper.
"If 'Chiquito' [Romero] hadn't been there, we would be talking about my substitutions again," Martino said in reference to the Paraguay game, when he was criticised for sending on Carlos Tevez and Gonzalo Higuain while his side were protecting a 2-1 lead.
"Our goalkeeper is confirming what he showed at the World Cup and he had another good game."
Martino also praised midfielder Javier Pastore, whose superb skill helped create the goal for Aguero as he fed a pass to Pablo Zabaleta for the cross to the forward.
"Pastore played a very good game," he said.
"He saw more of the ball than against Paraguay and had more continuity in his play. We have a lot of players who can cause problems."
And he added: "Today we didn't have as many chances as we did against Paraguay, but after Kun's [Aguero's] goal we could have finished it off. We had two good chances and we weren't able to take them.
"We live by results. If I get a lucky win, it is difficult to sustain that over time, so we have to maintain a style. I want to stay here for three-and-a-half years."
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