Four Italian clubs kept him in Serie A for thirteen straight seasons, Reggina and Atalanta and Palermo and Sampdoria from 2007 to 2020, more than 260 appearances built on being picked every week. Between 2004 and 2011 he won 60 caps, scored in the shootout against Japan that carried Paraguay to their first World Cup quarter-final, and came home with Olympic silver from Athens and a Copa América runners-up medal. Career record: 60 caps and 3 goals for Paraguay; club career at N.E.C., AS Reggina 1914, Palermo.
| 2002–2003 | Cerro Porteño |
| 2004–2007 | N.E.C. |
| 2007–2009 | AS Reggina 1914 |
| 2009–2011 | Atalanta BC |
| 2011–2015 | Palermo |
| 2015–today | U.C. Sampdoria |
| Paraguay | 60 caps, 3 goals |
Paraguay legends whose careers overlapped Barreto's
One rank above: Denis Caniza at #20.
One rank below: Nelson Haedo Valdez at #22.
Paraguay's editorial top five: Arsenio Erico · José Luis Chilavert · Carlos Gamarra · José Saturnino Cardozo · Julio César Romero.