Ireland, whose qualifying campaign came to a controversial end last year when a blatant handball by Thierry Henry set France up for a play-off winning goal, rarely looked troubled after first-half goals from Kevin Doyle and Liam Lawrence.
Doyle, one of nine starters who featured in that cruel night in Paris last November, put the hosts ahead on seven minutes, the front-man nodding in from close range after Paraguay striker Roque Santa Cruz headed onto his own bar.
Paraguay, who led the long South American qualification campaign throughout 2008 before finishing in third place, controlled much of the half but created few openings despite striker Rodolfo Gamarra looking lively on just his third cap.
The Paraguayans, preparing for Group F matches against Slovakia, New Zealand and holders Italy, were punished again on 39 minutes when Doyle neatly chested a Stephen Kelly cross into the path of winger Lawrence to smash home.
Paraguay defender Antolin Alcaraz tested Irish goalkeeper Kieren Westwood with a stinging drive just before the break but the visitors looked a shade of the side who beat Argentina and Brazil en route to their fourth successive World Cup appearance.
After a shaky start to the second half, Paraguay got back on top of possession and pulled a goal back on 57 minutes when Argentine-born striker Lucas Barrios, who obtained Paraguayan nationality last month, scored on his debut.
The Borussia Dortmund frontman, ignored by Argentina coach Diego Maradona despite scoring 19 goals in his debut Bundesliga season, finished well after a nice one-two between fellow Argentina-born winger Jonathan Santana and Santa Cruz.
However, Paraguay failed to trouble the Irish goal again and Giovanni Trapattoni's side went away with a morale-boosting victory ahead of the European Championship qualifiers which begin later this year.
