The Boys in Green boss has admitted that he did not agree with his new assistant's stance in 2002 when he walked away from the Ireland team before the World Cup
Keane was involved in a public disagreement with then-manager Mick McCarthy and the Football Association of Ireland (FAI) which resulted in his withdrawal from the Boys in Green squad prior to the tournament which was held in Japan and Korea in 2002.
"If you're going back to Saipan, way back in that time, I would have to say that my own view at that time, is that I would have disagreed with Roy," O'Neill told the Sunday Independent.
"I would have felt that, having qualified for the World Cup, it doesn't come around too often, for some great players it has never come at all, and here was this opportunity.
"I thought that would have been, regardless of what Roy would have felt about it before, this was a chance to participate in a World Cup and for a great player, even more so, from that viewpoint.
"So I would have had a disagreement with that."
Martin O'Neill was officially unveiled as Republic of Ireland manager in Dublin on Saturday November 9.