Paraguay and Spain are scoreless through 23 minutes in Johannesburg thanks in large part to Gerardo Martino making sure Xavi Hernández does not have an easy time on the ball.
Martino's six lineup changes have been deployed in a 4-4-2 with a flat midfield and Jonathan Santana partnering Oscar Cardozo at forward. It's a straight-forward, almost vanilla formation, but the tactics, specifically how they're treating Spain's playmaker, has cause Spain to stall out to start the match.
Martino has his team exerting a lot of pressure on Xavi Hernández. Any time Hernández gets the ball - even if he's in his half of the field - Paraguay is doing everything they can to get the ball off his feet, even if the means running multiple people at the midfielder.
Xabi Alonso and Sergio Busquets have had to go more of the work to get Spain into attack. The result has seen Spain start the match slowly, now half-way through the first 45 and still without a shot on goal.
I had speculated pre-match that, based on personnel, Paraguay could set-up like Switzerland, in a very conservative 4-4-1-1. Through the first quarter of this match, Paraguay has shown a very anti-Switzerland approach.