The Ospreys made hard work of their 14th straight win over Welsh opposition as Newport Gwent Dragons were defeated 20-10 at the Millennium Stadium on Sunday.
It keeps the Ospreys play-off chances alive but it could have been far more comfortable had they been disciplined in the first half and turned huge pressure into points.
But it was only in the final 20 minutes that the Liberty Stadium men put the seal on the game.
To get to that outcome, the Dragons’ try came via scrum-half Richie Rees, with Kris Burton converting and wing Tom Prydie landing a long-range penalty.
The Ospreys’ points came via a penalty try and a touchdown for scrum-half Tom Habberfield, while fly-half Dan Biggar converted both and also landed two penalties.
Meanwhile, Cardiff Blues kept alive their faint hopes of securing a place in next season’s new-look European Cup with a thrilling 17-13 success over Scarlets in a game marred by two red cards.
After lengthy discussions in the second half, Blues number eight Robin Copeland was dismissed for stamping, while Scarlets full-back Liam Williams, who had received a yellow card early on, was given another for killing the ball as play continued.
But it was the off-key kicking of Wales fly-half Rhys Priestland which proved costly for the Scarlets, although their losing bonus point means they are still almost certain of clinching a European spot.
In the first game of the Welsh regional double-header at the Millennium Stadium, the resurgent Blues, whose victories in their last two matches had rescued a disappointing season, enjoyed a flying start.
They gained an early position at the corner and although Copeland was held up short, Wales wing Alex Cuthbert joined his forwards and stretched to touch down on the line for an unconverted try.
Cuthbert was the victim in the next significant incident, rising to catch a Scarlets kick only to be taken out in mid-air by the over-enthusiastic Liam Williams, who was handed his first yellow card after referee Ian Davies had watched it again on the big screen.