O'Sullivan - who earned a 54-10 victory over the Welsh in his first game in charge in 2002 - insisted: "We've won three of our last four matches so there isn't a problem with confidence.
"There was no reason to drop anyone from the team at this juncture - they played well against France. With Gordon (D'Arcy) and Shane (Horgan) injured there weren't any areas of consideration. It wasn't a hard selection meeting," he confirmed.
With D'Arcy (hamstring), Horgan (thumb) and Munster flanker Denis Leamy (hamstring) ruled out, the Irish management have stuck with the side which were valiantly defeated 26-19 by France last weekend.
O'Sullivan has made a total of 15 substitutions over the past four playing weekends - with current replacements Marcus Horan (48 minutes) and Eric Miller (26) seeing the bulk of the action.
However, with none of the replacements forcing their way into contention, O'Sullivan is banking on his settled side to end the tournament on a high - and with a sixth straight win over the Dragons since 2000.
"It didn't come off against France and there are two ways of dealing with that. You learn from it or suffer from it. I like to look at what England did in this situation. They lost four Grand Slam games in a row.
"They said they'd get better because of it and they did - they went on to win a Grand Slam and the World Cup," added O'Sullivan.
"You can go backwards or forwards in this situation - you can't stand still. This Ireland squad is in the business of getting better."
* Leinster prop Reggie Corrigan (knee) and Munster scrum-half Peter Stringer (back spasms) both sat out today's training session. The duo are to have their fitness monitored over the next few days but are expected to line out in Cardiff.