A well-taken second-half goal from Derlis Gonzalez was the difference between the sides in a disjointed game in Group D, where both sides registered efforts that rattled the post, before Jorge Espericueta hit the bar in the final minute.
Paraguay had an early opening through an unusual avenue when Antonio Bresenio passed back to goalkeeper Richard Sanchez, who, under pressure, picked up the ball to give away an indirect free-kick. Jorge Rojas, who scored Paraguay's goal against Korea Republic, hammered the resulting set piece over the bar.
Mexico had their first chance on 20 minutes, with Armando Zamorano pouncing after Marco Bueno's shot was charged down, but his half-volley crashed off Diego Morel's upright.
Both sides were guilty of sloppy play that hindered any real progress, though the north American side got another sight of goal before half-time when a delightful flick from Jesus Corona finds Marco Bueno, but he dragged his shot wide.
Paraguay then had the ball in the back of the net courtesy of Arnaldo Sanabria, but it was ruled out after Derlis Gonzalez had blocked off Bresenio. However, seconds later, Gonzalez scored, Sanabria feeding him after fine work from Rojas, with an immaculate side-footed volley beyond Sanchez.
Gonzalez almost had a second soon after. He and Rojas combined well down the right flank, with the nippy midfielder skipping beyond his man before cutting the ball back to his team-mate, who rattled the same post as Zamorano had in the first-half.
Mexico's chances were few and far between as they sought a route back into the game, but Espericueta's late free-kick went agonisingly close to earning them a point, slamming against the bar to the despair of those in green.