The action kicked off on Friday night with title-chasing Ulster seeing off the challenge of third placed Cardiff Blues 26-17 at Ravenhill to temporarily leap-frog Leinster at the top of the table. In a must-win game for both title-challenging sides, it was the hosts who extended their winning run in all competitions to seven games and in doing so brought an end to The Blues' own six-game winning streak.
Elsewhere on Friday, Edinburgh Gunners, who had already qualified for next season's Heineken Cup, ensured that they will be the top Scottish side in the Celtic League for the second time in three seasons with a 22-16 triumph over Connacht at the Sportsground.
Friday's other game saw the Ospreys boost their Heineken Cup qualification chances and dented Munster's hopes of a Celtic League and Heineken Cup double with a convincing 27-10 victory at the Liberty Stadium. A brace of tries from the elusive Shane Williams and another from Jason Spice along with a faultless kicking display from Gavin Henson were enough to see off the challenge of the Heineken Cup finalists.
On Saturday, the Scarlets maintained their impressive Celtic League record at Stradey Park and stalled Border Reivers' hopes of Heineken Cup qualification with a 30-26 triumph. The visitors were denied their first ever win on Welsh soil when the Scarlets' Mark Jones crossed for the decisive score just four minutes from time.
The Dragons will take four points for the free weekend in this round of matches. Visit http://www.celticleague.com/ for match reports from all this weekend's games.