On 5 December 2014, Ramón left River Plate to become the manager of the Paraguay national team. He said "It's one of the biggest challenges of my career... There's a lot of work to do". Ramón first major competition was the 2015 Copa América. His first match in the Copa America was against Argentina which they drew 2-2. Ramón's second match was against Jamaica which they won 1–0. The last match of the group stages was against Uruguay which they drew 1-1. Paraguay finished 2nd with five points in their group. Paraguay won the quarterfinal against Brazil 1-1 (3-4 on penalties). Paraguay were hammered 6-1 by Argentina in the Semifinals which them go to the third group playoff which they lost 2–0 against Peru which made them fourth in the Copa America. Ramón continued in the national team. On the Copa America Centenario, Paraguay were out of the competition in the group stage, by drawing against Costa Rica and losing to Colombia 2-1 and the US 1–0. On 12 June 2016, following an unsuccessful run at Copa América Centenario, he resigned as manager of Paraguay.