Toulon turned on the power in the second half to secure a 20-16 win at the Aviva Stadium and end Leinster's interest in this season's European Champions Cup.
With their bulldozing bench coming to the fore, the defending champions erased a 16-5 interval deficit thanks to a penalty try, a maul effort from replacement hooker Anthony Etrillard and a Tom Taylor penalty.
A knock-on denied Mamuka Gorgodze’s late, potentially bonus point-earning, try and Leinster, with Jordi Murphy in the sin-bin, could not muster a response in the dying seconds as they fell to their fourth successive defeat in Pool Five.
Leo Cullen's men were the better side up to the break, Jonathan Sexton converting a 17th-minute penalty try and firing over three penalties. However, Toulon silenced the vast majority of the 44,925-strong crowd with a clinical display over the closing 40 minutes.
The home fans had drawn encouragement from a high-energy start from Leinster, with Eoin Reddan making good use of quick ruck ball and Dave Kearney and Isa Nacewa kicking cleverly.
Sexton booted the hosts in front after Richardt Strauss got his hands on a 10th-minute ruck ball, and another breakout - inspired by Luke Fitzgerald - led to Duane Vermeulen seeing yellow for a cynical ruck offence.
Fourteen-man Toulon denied Leinster from the resulting five-metre scrum, Bryan Habana preventing a looping pass from getting to Dave Kearney near the left corner. However, as the penalties continued to mount up, Toulon infringed at a five-metre maul as Leinster powered towards the line and referee Wayne Barnes awarded the penalty try which Sexton converted.
Ten minutes later, Toulon had the deficit halved. Man-of-the-match Juan Smith initially peeled around the front of a close-in lineout, Mathieu Bastareaud made the hard yards closer to the posts and Smith then popped up on the left, finishing off a potent attack.
Eric Escande miscued his conversion attempt and Sexton subsequently slotted over a central penalty to reward Leinster for a promising spell that was sparked by a rampaging Rhys Ruddock run. Poor discipline from Delon Armitage, who was penalised for a late tackle on Reddan, handed Sexton and Leinster three more points on the stroke of half-time.
Escande pushed a kickable penalty wide on the resumption and Leinster's aggressive defence frustrated Toulon through 18 absorbing phases. Pressure from Rob Kearney was just enough to force a fumble from Drew Mitchell in a try-scoring situation.
However, Leinster scrum was to buckle twice in quick succession moments later as a penalty try, converted by replacement Taylor, closed the gap to 16-12 on 57 minutes.
With the French giants holding momentum and with Sexton handing possession back to the visitors, they used a subsequent penalty to take the lead. Jocelina Suta's lineout take set up the bulky Toulon pack for a rumble over the line with Etrillard scoring.
Taylor failed to convert but tagged on a 73rd-minute penalty to open up a four-point gap, a deserved return for Toulon's dominance of second-half possession and territory.
The title holders' only blip was missing out on the bonus point, a slight fumble at the preceding ruck just denying Gorgodze after Murphy, pinged for a maul infringement, became the fourth Leinster player to the sin-bin in these back-to-back clashes.