Gavin Henson's return as a Welsh regional player following a five-year absence ended in a bonus point defeat as Leinster ran out comprehensive 39-16 winners over the Dragons.
Henson, 35, who had spells at London Welsh, Bath and Bristol after leaving Cardiff Blues in 2012, kicked three penalties while the Dragons were also awarded a penalty try in this PRO14 contest.
However, Leinster controlled the game and were 13-6 up at half-time after scrum-half Jamison Gibson-Park scored a try, converted by fly-half Ross Byrne -- who also kicked two penalties.
The visitors also had a penalty try and touchdowns from wing Jordan Larmour, flanker Dan Leavy and replacement Cathal Marsh. Byrne added the extras twice and Marsh converted his own try. Henson opened his account with a 30-metre penalty early on and the signs were favourable for the Welsh region against last season's beaten play-off semifinalists.
But Leinster, who ran out 54-22 winners at Rodney Parade just over six months ago, found their feet with territorial advantage for the rest of the half.
They gained parity with Byrne's first penalty and went ahead when Gibson-Park dived around the corner of a scrum on the home line and evaded an attempted tackle by hooker Elliot Dee for a try that Byrne converted.
Henson booted his second penalty but, in the final minute of a relatively tame first half, Byrne restored the seven-point lead with another penalty.
Leinster imposed their authority early in the second half as lock Scott Fardy caught the ball from an attacking line-out that resulted in a surge and a yellow card for home second row Matthew Screech when he pulled down the ruck with a touchdown inevitable.
Referee Mike Adamson ran between the posts for the penalty try, which is not converted these days as it is taken for granted. Henson kicked his third penalty but Leinster went further ahead when Larmour strolled in unopposed from 10 metres.
Isa Nacewa continued to lead by example for the visitors with some deft kicks and Leavy sealed the result with a simple run-in near the posts. The Dragons were awarded a penalty try when Ashton Hewitt was high tackled by Adam Byrne but Leinster finished on top when Marsh was at the back of a drive over the line - and he added the extras himself.