Richard Strauss, Luke Fitzgerald and Heinke van der Merwe followed Horgan’s lead for Leinster, without Brian O’Driscoll, while he notched another early in the second half.

Ulster salvaged some pride with tries from Pedrie Wannenburg and Craig Gilroy but Leinster’s first-half blitz meant they always had a mountain to climb.

Leinster now sit second 14 points behind leaders Munster, who beat Scarlets 13-6, with Ulster dropping down to third and two points further adrift.

Elsewhere on Saturday Robert Barbieri helped Treviso send Glasgow to second bottom in the Magners League scoring in their 19-16 win.

Barbieri, who played in four of Italy’s RBS 6 Nations matches, including the famous win over France, crossed the whitewash after the break as both teams traded scores.

Glasgow centre Graeme Morrison joined Barbieri in scoring while Ruaridh Jackson and Willem de Waal both slotted three penalties each – with the latter’s drop goal the difference.