Quinn sided with Mick McCarthy in the infamous bust-up that ended with Keane walking out of the Ireland team at the 2002 World Cup finals and then revived his relationship with the firebrand legend by hiring him to manage Sunderland in 2006.
"Had we known it was going to be so serious in that team meeting, we should have just abandoned that team meeting," Quinn told the Sunday World of the showdown between McCarthy and Keane.
"It was a really difficult time for us and it doesn't get any easier. I appreciate that it was 1000 times more difficult for Roy Keane.
"I was pleased in many ways when Roy eventually came to Sunderland as manager and did as well as he did. I was pleased that there was more to my relationship then than somebody who was part of a group who supported Mick and played for Mick in that tournament, rather than saying it was Roy we should have been sticking up for."
On his Sunderland experience, Quinn said: "He kind of swept into town, and the whole city just backed him accordingly. The players responded, and we did what we could. We bought players to help him along the way.
"But it was great to see him in that first year, that first 18 months, two years, obviously his most successful time as a manager, and to see the control he had over not just his players but the club and the city as a whole, I always felt that he was going to go on somewhere bigger and do it on his own.
"Now, he chose to go number two for the last lot of years, but I would always still argue the point that he's number one, and there's still a number one in him somewhere to redo what he did at Sunderland."