It emerged this week that a group of Black Cats stars had shelved a planned trip to Cheltenham Festival amid a run of six league games without a win which has seen the club slide ever closer to the relegation zone.
Reports suggested O'Neill had pulled the plug on the horse-racing jaunt, but sources on Wearside insisted the decision had come from senior members of the squad.
But whoever was responsible, the manager insisted it was the correct course of action ahead of Sunday's crucial clash with Norwich.
O'Neill said: "Initially, they had asked for it, as they had done for the last number of years, and it's fine.
"But when you are looking at some results, enjoyment can come later. Let's go and win some matches first, that would be the most important issue.
"The players do understand - I think they have always done that. Since I have come into the football club, they felt the same a while back.
"We need to win some matches - it's vitally important that we do. We have still a number in which to do so and we have got points to play for.
"My own view is that it was the proper thing to do."