The Reds defender played 90 minutes at left-back against the South Americans, who were in Ireland as part of their preparations for the World Cup finals.
The home side took the lead on eight minutes when Kevin Doyle bundled the ball over the line after Manchester City forward Roque Santa Cruz had headed against his own crossbar.
Paraguay then kept possession well but lacked incision in the final third. They rarely tested the Irish goal and found themselves 2-0 down at the break after Stoke City’s Liam Lawrence fired home after good work from Doyle.
The South American side, who will face Italy, Slovakia and New Zealand at the World Cup, pulled a goal back just before the hour through debutant Lucas Barrios, but it wasn’t enough to prevent defeat, despite bossing the game for long periods. The full-time statistics made clear where the problem lay: the visitors had twice as much possession but only half as many shots on target.
O'Shea and his Ireland team-mates may not be going to South Africa, but they can't embark on their summer holidays just yet: Ireland host Algeria in another friendly this Saturday 29 May in Dublin.
Next in action: Patrice Evra’s France play Costa Rica in Lens on Wednesday 26 May, while Chicharito is expected to feature for Mexico v Netherlands in Germany.