Goals in either half from Kevin Doyle and Alex Pearce saw Ireland claim a comfortable 2-0 victory over Oman at a sparsely-populated Aviva Stadium.
Both goals game via corners from Robbie Brady.
Lifford keeper Shay Given was handed his first Republic start after coming out of international retirement while Derry's Darron Gibson made his return from a serious knee injury.
Shay was replace by Rob Elliot at half time and Gibson played 70 minutes.
Despite dominating their guests, it was only when O'Neill reverted to a more orthodox 4-4-2 formation with the introduction of Robbie Keane, Shane Long and Aiden McGeady that Ireland started to create more chances.