And after falling agonisingly short of that achievement last term when they lost their final game of the season to Munster a week after beating Northampton at the Millennium Stadium, Nacewa admits he and his colleagues are desperate to be celebrating the double at the RDS.
"It would be special to achieve the double. It hasn't been done before and we probably weren't in the right frame of mind last year," Nacewa told the Irish Times.
"That being player-driven this year, coming from the leaders all the way down, is important.
"It's not like there's been anything officially said. But there was word around the dressing-room after the Heineken Cup Final that we wanted to celebrate the win as we probably deserved. But then it was just about getting back to reality really quickly and focusing on another final this week. We probably didn't do that as well last year, but this year we have.
"Defeat would hurt us. There was a bitter taste in our mouth last year after we lost to Munster. We were on such a high and we all came crashing down pretty quickly and that was the way we finished our season."
Consistency has been the key to success on both fronts for Leinster this season. Rarely have they fallen short and never when it has really mattered.
In addition to becoming the first side to go through an entire Heineken Cup campaign unbeaten, Joe Schmidt's men finished 10 points clear at the top of the PRO12 table.
There have only been three defeats all season and two of those came when a whole host of star names were away at the World Cup.
Nacewa believes the ability to follow huge Heineken Cup fixtures with equally impressive domestic results has been a major positive so far, although he's aware that such a significant step will mean very little if the Ospreys leave Dublin with a win this weekend.
"The whole squad has built on last year and worked on consistency," added Nacewa.
"Off the back of Heineken Cup wins, the following week the team has been completely different and we've still been able to grab wins, whether they've been pretty or not. That's been the biggest strength in our squad this year, our strength in depth.
"We're up on a high at the moment. But we've got to be realistic about how good the Ospreys are. They've won the last six matches and are on a bit of a roll. They've had a week off to recover also, so they are going to be in good shape.
"We do try to keep the two competitions separate but they've been a bogey team for us over the last couple of years. From their point of view, to knock off the European Champions in the last game of the season would be special for them."