Heineken Cup holders Leinster took a giant stride towards this season's quarter-finals with an 18-13 win at Bath, who are now facing an early European exit.
Ireland fly-half Jonathan Sexton kicked six penalties - three during a 15-minute spell in the second period - while his two clinching goals arrived during the closing seven minutes.
Bath went close to collecting one of their most notable Heineken Cup scalps in recent seasons when England wing Matt Banahan barged over from close range after 65 minutes.
Centre Olly Barkley, who slotted two first-half penalties for a 6-0 lead, added the conversion to edge Bath one point in front, but Sexton nudged Leinster towards a priceless Pool Three away win when home skipper Francois Louw infringed.
And to complete a miserable two-minute spell for South African Louw, he was then sin-binned as Bath ended the game a man short.
Bath now head to Dublin for next Saturday's return fixture and, while they are not mathematically out of quarter-final contention, it will require a Herculean effort to turn things around, with a losing bonus point providing scant consolation.