I really like Javier Mascherano, but I think he hasn't reached the same prominence of Luis Monti among his contemporaries (although we could discuss whether he was a pure defensive midfielder). I'd also question his superiority over Ángel Perucca, but I'd agree over Antonio Rattín. In any case, obviously that excludes others as José María Minella, Néstor Rossi and Fernando Redondo.