A Brian O'Driscoll try in the final minute handed Lienster a bonus-point 27-10 win over Brive in the Heineken Cup on Saturday.
The result puts the champions five points clear of London Irish, who play the Scarlets on Sunday, in Pool Six.
O'Driscoll stormed over in the right corner for his side's fourth try having earlier been given a stern examination by Brive, who have now lost all five of their fixtures.
Leinster led 7-0 at the break courtesy of a penalty try but the game improved as a spectacle in the second period as Isa Nacewa, Gordon D'Arcy and O'Driscoll all touched down.
Brive, who produced a determined defensive effort in marked contrast to some of their earlier Heineken Cup matches this season, scored two tries of their own through Retief Uys and Scott Spedding.
Brive fly-half Luciano Orquera pulled an early penalty chance wide and both sides struggled to string together any continuity in their play during a scoreless, instantly forgettable opening 20 minutes.
Leinster, playing their first game for three weeks, belatedly came to life in the 23rd minute when left winger Isa Nacewa's chip ahead forced the covering defender to carry the ball back over his own line, giving the Irish side a five-metre scrum.
And following a succession of infringements from Brive's pack, referee Andrew Small lost patience and awarded the hosts a penalty try.
Jonathan Sexton added the conversion for a 7-0 lead and Leinster were immediately back on the attack and pressing for a second score.
Brive, however, stood firm in defence close to their own line and managed to hold out until half-time without further damage.
Sexton added a penalty early in the second half to stretch Leinster's lead to ten points, although the TMO was required to determine the ball had actually gone between the uprights.
And, two minutes later, the home side assumed total control when a flowing move ended with Nacewa crossing in the left corner for his first try in the Heineken Cup.
Slick handling from Rob Kearney, Kyle McLaughlin and Brian O'Driscoll resulted in a simple finish in the left corner for the Kiwi flyer.
But Brive once again showed resilient qualities that had been hitherto lacking in their European campaign, battling their way back into the contest with a 59th-minute try.
Second row Retief Uys broke straight through the middle of a rolling maul to storm over the whitewash despite the attentions of a trio of tacklers.
Horacio Agullo missed the conversion attempt from wide on the left to leave Brive trailing 15-5 entering the final quarter.
But Leinster's response was impressive, a sustained period of pressure ended with D'Arcy rounding the midfield defence on an arcing run for his side's third try.
Sexton's conversion was successful to give open a 22-5 advantage and leave the Irishmen with quarter-of-an-hour to chase the four-try bonus point.
That looked unlikely when Spedding's scored Brive's second try in the 76th minute, the full-back side-stepped his way out of traffic before sprinting to the line.
However, there was just enough time left for O'Driscoll to have the last word, diving over in the left corner to earn the bonus point and keep his side on course for a place in the last eight.
Leinster will qualify for the quarter-final if they beat London Irish at the Madejski Stadium in their final pool game on January 23.
Tries: Penalty try, Nacewa, D'Arcy, O'Driscoll
Leinster: 15 Rob Kearney, 14 Shane Horgan, 13 Brian O'Driscoll, 12 Gordon D'Arcy, 11 Isa Nacewa, 10 Jonathan Sexton, 9 Eoin Reddan, 8 Jamie Heaslip, 7 Shane Jennings, 6 Kevin McLaughlin, 5 Nathan Hines, 4 Leo Cullen (c), 3 Stan Wright, 2 John Fogarty, 1 Cian Healy.
Replacements: 16 Bernard Jackman, 17 Mike Ross, 18 CJ van der Linde, 19 Malcolm O'Kelly, 20 Sean O'Brien, 21 Paul O'Donohoe, 22 Shaun Berne, 23 Girvan Dempsey.
Brive: 15 Scott Spedding, 14 Nicolas Jeanjean, 13 Jamie Noon, 12 Lachlan Mackay, 11 Horacio Agulla, 10 Luciano Orquera, 9 Jean-Baptiste Pejoine, 8 Antoine Claassen, 7 Fabien Domingo, 6 Alix Popham, 5 Damien Browne, 4 Retief Uys, 3 Pascal Idieder, 2 Steve Thompson, 1 Pablo Henn.
Replacements: 16 Guillaume Ribes, 17 Petrisor Toderasc, 18 Christian Short, 19 Simon Azoulai, 20 Shaun Perry, 21 Viliame Waqaseduadua, 22 Régis Bianco, 23 Pat Barnard.
Referee: Andrew Small (England)