The hosts had taken a 16th minute lead when Jack Byrne’s free kick was deflected in by Italian defender Rolando Mandragora.
Rea was then booked on 21 minutes before the visitors levelled on 28 minutes when Gaetano Monachello found Marco Benassi who volleyed past Daniel Rogers.
The Azurri went ahead before half time as Valerio Rosseti headed home, while in the second period, Alessio Romagnoli made it 3-1 on the hour mark.
Ireland pressed for a leveller, but Italy wrapped the game up on 82 minutes when Darragh Lenihan turned through his own goal.
Rea will now travel to Slovenia for another qualifier on Monday evening.