Ulster got their European Cup campaign off to a flying start on Saturday with a breathtaking 30-3 demolition of triple champions Toulouse.
Leinster then made it a double Irish celebration with a 37-20 Lansdowne Road victory over Gloucester.
Ulster, who took the title in 1999, saw off their French visitors with two tries from winger Andrew Trimble and a third from scrum-half Issac Boss with the rest of the points coming from the boot of David Humphreys.
It was Toulouse's worst result since the 40-10 defeat to Leinster in the 2001-2002 campaign.
"It was a brilliant team performance," Ulster coach Mark McCall said after the win in Belfast.
"Maybe there is a sense of frustration at not getting a bonus point but in reality how can you be frustrated after winning 30-3 against Toulouse?" he said.
In Dublin, Gordon D'Arcy gave Leinster an early lead but Gloucester nipped ahead 10-7 thanks to a great try from Mark Foster.
Leinster then hit 23 points without reply, which included Felipe Contepomi and Stephen Keogh tries.
Jack Adams' touchdown cut the lead to 10 points but Shane Horgan's try secured the bonus point for Leinster.
Stade Francais, running away with the French championship, set out in their quest for a first ever European title with a resounding 45-10 win at Italian side Calvisano. The win also secured a bonus point.
Geoffroy Messina, Julien Arias, Ignacio Corleto, Mauro Bergamasco, Radike Samo and Julien Saubade all socred tries for Stade.
Another Italian team, Treviso, were beaten 25-10 by Perpignan.
Cardiff came back from Bourgoin with a tense but hard-fought 13-5 win with international flanker Martyn Williams scoring the only try with Ben Blair adding the conversion as well as two penalties.
It was the Blues' first European Cup win on French soil.
On Friday, Neath-Swansea overcame the loss of star center Gavin Henson to clinch a dramatic last minute 17-16 win over English Premiership champions Sale.
James Hook held his nerve to convert Shane Williams' injury-time try.
Charlie Hodgson's second-half penalties had looked to been enough for Sale, before Hook had the last word with a conversion of Williams' second try of the tie.
Llanelli ensured it was a double-winning start for the Welsh, who have never won the trophy, with a battling 32-25 win at London Irish.
French side Agen edged Edinburgh 19-17 while Border dismissed Parma 35-3. Yesterday, Munster traveled to Leicester.