Leinster 42 Bath 15
Tries from Bath back rowers Francois Louw and Sam Underhill were dwarfed by the defending champions' six-try tally - Jack Conan, man-of-the-match Rory O'Loughlin, James Lowe, Adam Byrne, Dan Leavy and replacement Jamison Gibson-Park all touched down at the Aviva Stadium - as the result ruled Bath out of contention for the knockout stages.
While they remain two points behind leaders Toulouse, Leinster are now assured of at least a second-place finish in the pool. A win of any hue in their round five home game against Toulouse on January 12 will mean they go to Wasps for the final game top of the pool.
After seeing his charges struggle to create momentum a week previously at the Rec, head coach Leo Cullen was pleased with Leinster's application on a blustery night in Dublin.
"We knew about the threats Bath have in their team going into last week," said Cullen.
"It's one thing knowing about it, but then it's how do we deal with it? We didn't deal with it particularly well at times last week. I thought we were better around the contact area, even though we gave away a penalty and three points at the very start of the game.
"Overall, I thought we played with a bit more attacking intent and were able to move Bath around a bit more. I thought the guys were very clinical in terms of taking some of the opportunities when they came along. Particularly in the first half."
Cullen stressed, however, that there are areas of Leinster's play that require attention ahead of their Christmas return to Guinness PRO14 action.
"We probably don't make a great read on the lineout (for the first try) and then we find ourselves defending a series of attacks from Bath," he said.
"I thought they came with a very direct focus in terms of the way they tried to attack us.
"They're a team that have got a ton of resources behind them and they've got so much quality. For us, there was maybe a couple of times in the first half where we don't quite connect defensively. There's definitely lots of things we can get better at."
European Champions Cup
Munster head coach Johann van Graan was left to rue missed opportunities and unfavourable refereeing decisions after seeing his side lose the second of their Champions Cup Pool Two back-to-back matches against Castres Olympique by a single point.