The defending champions were second best in the first half but turned that around after the break with 15 unanswered points to make it 17 wins in their last 19 tournament matches and their fourth in four meetings with Leinster.
 
The defeat leaves Leinster, who had never previously lost back-to-back home games in the same season of a Champions Cup campaign, pegged and stranded at the basement of Pool 5 with just two points.
 
In front of almost 45,000 fans at a vibrant Aviva Stadium, who were, however, silenced by Toulon’s comeback on their way to a 20-16 victory, Leinster’s bravery ultimately was not enough to see off Toulon’s experience and power.
 
The two European heavyweights have won six of the last seven titles between them – Leinster in 2009, 2011 and 2012 while Toulon have since reigned supreme in 2013, 2014 and 2015 with an unprecedented hat-trick of crowns – and in the end Toulon proved why they are the defending champions.
 
They are now six points behind group leaders Wasps but have a rearranged home game in hand to play against Bath Rugby in the new year.
 
Johnny Sexton had opened the scoring with penalty after just 10 minutes and there was more woe for Toulon when No 8 Duane Vermeulen was sent to the sin bin for a 10-minutes break after English referee Wayne Barnes caught him with his hands in a ruck.
 
With a man advantage Leinster looked odds on to construct the first try of the match but an alert interception by Bryan Habana rescued Toulon – albeit briefly.
 
Because the Irish province took advantage of Vermeulen’s absence to have the champions in rapid retreat from a driving maul, referee Barnes having no hesitation in awarding a penalty try when the French forwards pulled them down illegally.
 
Sexton added the conversion for a double point advantage but, once restored to a full 15 with Vermeulen’s return they hit back in style.
 
Flanker Juan Smith – the Heineken man-of-the-match – took the ball on the peel from a line-out and then battering ram Mathieu Bastareaud made inroads before Smith finished what he had started with a smart try.
 
Eric Escande failed with the conversion attempt and when Toulon were penalised for the seventh time Sexton punished them with a second penalty.
 
The message clearly did not get through to the champions as they presented Sexton with yet three more points just seconds before the break for an 11-points advantage that will have left Toulon Director of Rugby Bernard Laporte with plenty to stay before the resumption.
 
Escande clearly had not packed his kicking boots for the trip to the Irish capital as he sent another penalty chance wide and Leinster defended wave after wave of Toulon attacks over 18 phases with real determination.
 
And replacement hooker Sean Cronin came to Leinster’s rescue with a crucial try-saving tackle on Drew Mitchell as the Wallaby wing threatened to add another Toulon try – and then Vermeulen was held up just when he threatened to crash over.
 
The Toulon pack were now in full cry and when the Leinster scrum went down twice close to their line Barnes awarded his second penalty try of the contest, three-times capped All Black Tom Taylor adding the conversion to close the gap to just four points as the contest went into the final quarter.
 
That was wiped out at a stroke as a Toulon driving maul predictably ended with replacement hooker Anthony Etrillard getting the champions’ third try as they went ahead for the first time after 66 minutes.
 
That was 12 points without reply – make that 15 as Taylor landed a well struck penalty – and to make matters worse replacement Jordi Murphy failed to go the distance when he was yellow carded with three minutes remaining.