Dan Leavy, James Tracy, Cian Kelleher, Luke McGrath, Max O’Reilly and replacement David Hawkshaw were the try scorers for the Irish province – a penalty try completing the seven-score rout.

Harry Byrne added six conversions and a penalty for Leinster – with the Welsh region unable to cope with the unrelenting Irish dominance.

Scarlets were in the contest for the first twenty minutes – scrum-half Dane Blacker going over after Uzair Cassiem’s stunning run from halfway. Sam Costelow added an early penalty and converted the try to give the hosts a 10-7 lead after the opening quarter.

But the strength of the PRO14 champions soon showed as they added three tries before the interval to lead 29-13 at the half.

The commanding position allowed head coach Leo Cullen to introduce Irish prop Tadhg Furlong – who made his first appearance since suffering an injury against England in the Six Nations last year.

Elsewhere in the PRO14, a JJ Hanrahan drop goal with the final play of the game helped Munster Rugby avoid a spectacular upset at the hands of Benetton Rugby - the Irish province overcoming their Italian counterparts 18-16 at the Stadio Comunale di Monigo.

Current Heineken Champions Cup holders Exeter Chiefs overcame Worcester Warriors 21-17 to stay in contention at the top of the Gallagher Premiership.

First half tries from lock Jonny Gray and centre Ian Whitten gave the visiting side a 14-7 lead at the interval before Ollie Devoto scored within two minutes of the restart.

Despite pressure from Worcester, the defending English champions were able to hold on for victory at Sixways Stadium.

Northampton Saints outlasted Gloucester Rugby in an all-Heineken Champions Cup battle at Kingsholm.

A five-minute double from Shaun Adendorff mid-way through in the second half secure a bonus point victory for the visitors after earlier tries for Taqele Naiyaravoro and Rory Hutchinson - Billy Twelvetrees scored 16 points in response for Gloucester.

In the Top 14, Lyon and Toulon suffered narrow defeats at the hands of European Rugby Challenge Cup sides Pau and Brive respectively – Lyon losing out 18-17 and Toulon falling 25-23 in an enthralling Saturday afternoon of Top 14 action.

Guinness PRO14 holders Leinster Rugby demolished Scarlets 52-25 in a stunning seven-try performance at the Parc y Scarlets on Saturday evening.