Shane Horgan scored his 63rd and 64th career tries in a man of the match display in the RDS, which also marked the Boyne man's 190th Leinster appearance.
Isaac Boss touched down for his second try in 10 appearances to date, while Shaun Berne continued his comeback from injury with a 75 minute shift in which he too scored a try.
The team is expected to be announced on Friday lunchtime.
Speaking ahead of Sunday's game Leinster Coach JOE SCHMIDT said that the squad are determined to build on their recent good run of results against a strong Ospreys side.
"We're expecting an even tougher test this weekend. They got a win against Connacht in the last minute which was obviously a pretty good performance considering Connacht weren't too far from (being) full strength.
"We found them a very tough nut to crack when we were in Galway a few weeks ago so, for Ospreys to have done that is a very good effort. They've got some real talent in their young guys whom they have recently given game time in the LV= Cup so they might add something that we don't know so much about.
"We had a few bumps and bruises (out of the Dragons victory), but that is pretty much it and we're hopeful that those guys will be available at the end of the week. We have a nine-day turnaround so we've got enough time to get anyone with bumps and bruises back on their feet.
"I'm not sure of how bad the injuries are with Ireland. We believe that Luke (Fitzgerald) will be out for 4 to 6 weeks, so we're hopeful that he'll be available to us for at least the Clermont return fixture. I spoke to Rob Kearney today and we won't know about him until Tuesday when they have a look around his knee.
"The last few wins are not just about (being good for) confidence. It's about points on the table. Ulster went away and got a really good win against Cardiff and that allowed them to stay in front of us. Ospreys got their win in Connacht. So if you're not winning, then you're going to be very quickly behind the eight-ball and chasing. We want to try and get some kind of established break and make it into the top four.
"The tempo that the Ospreys play with makes them dangerous. In the loose forwards they have the likes of Jerry Collins and Marty Holah who are two really formidable players. They also have real talent out wide. (Richard) Fussell has been playing well for them.
"Nikki Walker is a big strong athletic fella and even though he was called up by Scotland, I'm not sure where he sits (in terms of availability) because he did play a couple of weeks ago against the Dragons when Scotland were playing.
"Their half-backs were really impressive in their win over Leicester in the LV= Cup. To do that against formidable opponents was pretty impressive in tough conditions. They scored six tries and their new out-half had a hand in at least four of those six tries."
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