The visitors got points from Andrew Porter, Dan Sheehan, Garry Ringrose, Josh van der Flier (2), Ed Byrne, and Ross and Harry Byrne Harlequins.
With Ireland prop Porter driving over for a soft try and flyhalf Ross Byrne, in place of crocked star Johnny Sexton, converting, a ruthless Leinster team was off to a great start.
Following the award of a 42-meter penalty for a ruck offense by Scotland star Russell, Racing’s hooker Camille Chat was sin-binned for numerous breakdown violations shortly after.
Leinster made their extra man count by going through phases to make room for unmarked hooker Sheehan to cross. Ross Byrne converted with skill to give Leinster an 11-point lead.
Just before halftime, a complex handling move culminated in an overhead pass from roving winger James Lowe, sending skipper Ringrose over, with Ross Byrne adding the extra points once more. This made the score 21-3.
Ringrose nearly scored another try early in the second half, but they were unable to take advantage of territory and possession due to a series of handling mistakes.
After a tap penalty, World Player of the Year Van der Flier scored Leinster’s fourth try, which Ross Byrne converted once more.
After that, Ringrose fed Ed Byrne, who scored in the 70th minute with Harry Byrne converting before Wade crossed and Russell added the extras.
In a different setting, Harlequins started their Champions Cup campaign by losing to Sharks 39-31 in a thrilling game on their first trip to South Africa.
The London team did get a crucial bonus point for scoring four tries, but the 14-man Sharks scored a fifth try and got two crucial bonus points in a late rally to win in Durban.
When prop Ox Nche was sent off midway through the second half for a head-on collision, the Sharks lost a player. Center Andre Esterhuizen scored two tries for Harlequins in response.
Wing Josh Bassett crossed for his second attempt as Quins made it 32-31 preceding full-back Boeta Chamberlain crossed for the fundamental pursue Sharks in the 79th moment to get a renowned triumph.
Bongi Mbonambi, a hooker, and Makazole Mapimpi, a winger, both crossed for two tries for the Sharks. Winger Werner Kok joined fullback Chamberlain on the scoresheet.
After five minutes, Quins scored their first try when wing Bassett, who signed for the club after Wasps folded, was found by fellow wing Cadan Murley with a fantastic long pass after a lineout close to the home team’s line.
Fly half Tommaso Allan converted to give the visitors a 7-0 lead.
Curwin Bosch scored the extras to level the score, then converted a penalty to give the home team a 10-7 lead. Sharks then scored a second try to increase their lead.
Back in Sharks uniform, South Africa winger Mapimpi crossed for his first try, making the score 17-7 in favor of the home team midway through the first half. Curwin’s second conversion added the extras.
After a dominant Sharks scrum five meters from the Harlequins line, Mapimpi danced and stepped past defenders to cross the whitewash and score his second try, making the score 22-7.
Sharks scored a fourth try after the break when wing Kok ran on to his kick-and-chase to score in the corner, earning the home team a bonus point. The conversion was won by Bosch.
After that, the Sharks were reduced to 13 men, with hooker Mbonambi receiving a yellow card for persistent infringing and prop Nche receiving a red card for colliding head-on with Jack Walker.
Center Esterhuizen crossed for two tries for Harlequins, and Bassett scored twice for Sharks before Chamberlain won the game for them.