Llanelli hammered arch-rivals Swansea 62-6, Leinster belted a winless Newport 42-14, and Borders upset fellow Scottish side Glasgow 33-12.
All the drama was at Stradey Park, where referee David McHugh showed red cards to Swansea pair Gavin Henson and Dean Thomas in the first half to end the match as a contest.
Llanelli ran in tries at will, with fly-half Stephen Jones picking up 32 points.
The loss continues a sorry season for Swansea under Australian coach John Connolly, but not as sorry as Newport’s. The Black and Ambers are now nine matches for nine losses as their horrible season continued in Dublin.
Leinster’s Irish international scrum-half Brian O’Meara kicked 22 points in the four-tries-to-none drubbing of Newport.
With six straight defeats the Black and Ambers will have to scrub this Celtic League campaign and focus their efforts on the upcoming challenges of the Heineken Cup and Welsh Premiership.
In the Scottish derby Borders shock win over Glasgow means the Glaswegians are struggling to earn a home quarter-final.
This is the result many Borders supporters had been predicting, if form continues on the same upward spiral next season, Borders could make a serous challenge for top eight status. Borders finish their debut Celtic League season away to Newport next weekend.
Results
Lllanell 62 Swansea 6
Leinster 42 Newport 14
Borders 53 Glasgow 19
