Defending champions Leinster ran in seven tries in a 52-27 demolition of Bath in Dublin on Saturday to go six points clear at the top of Pool Three and move closer to a European Cup quarter-final spot.
A week after beating the English side 18-13 in Bath, the Irishmen ran rampant, making sure of a bonus point after Rob Kearney, Luke Fitzgerald (2) and Jonathan Sexton had all scored tries.
Scrum-half Eoin Reddan, Rhys Ruddock and Ian Madigan piled on the agony for the visitors, while Bath battled to score three second-half tries through Stephen Donald, Dave Atwood and Ben Williams.
In the group's other match, second-placed Glasgow drew 13-13 at Montpellier, with Rory Lamont, back in Scottish rugby after a spell with Toulon, scoring his team's only try.
"We are obviously delighted to get the five points and with the tries and also some of the running lines," said Leinster coach Joe Schmidt after Bath suffered their heaviest ever defeat in the history of the tournament.
Leicester relaunched their bid for a place in the quarter-finals with a gritty 23-19 win over French heavyweights Clermont.
The 2001 and 2002 champions, suffered their first defeat in Pool Four last week when they succumbed 30-12 in Auvergne.
However, a solid second-half defensive performance, combined with the boot of England fly-half Toby Flood, kept the Tigers on course for an 11th quarter-final appearance in 15 years of European Cup competition.
Ulster stayed top of the group after a six-try 46-20 rout of Aironi, a bonus point win that kept them two points ahead of Leicester.
Andrew Trimble, Tom Court, Craig Gilroy and replacements Robbie Diack and Adam Macklin were all on the mark for the visitors, while a first-half penalty try added to Italian misery.