Ulster remain on course for a Pro 12 semi-final berth after a comprehensive 30-6 win over rivals Leinster on Saturday.
Third-placed Leinster could have gone top with victory at Kingspan Stadium, but were instead well beaten by the hosts who have now lost just once in their last five outings.
A first-half penalty-try and further five-pointers from Paddy Jackson and Jared Payne saw Les Kiss' side home, while Leinster lost both Rob Kearney and Luke Fitzgerald to yellow cards and could only muster two penalties from Jonathan Sexton.
Ulster's win keeps them a point clear of nearest rivals Scarlets, who ran out 34-20 victors over Newport Gwent Dragons at the Principality Stadium.
Centre Scott Williams enjoyed a memorable return to action, scoring one try and creating two others on what was his first appearance since sustaining a serious knee injury in September.
Gareth Davies, Steve Shingler and Steffan Evans also crossed for the Scarlets as they successfully secured European Champions Cup qualification, while Adam Hughes and Adam Warren replied in kind for the Dragons, who remain in 10th place.
Ospreys continued their recent dominance of Cardiff Blues with a thrilling 40-27 win.
Having won their last four Pro 12 games, the Blues went into the game confident of ending a nine-match winless streak against their Welsh rivals and led 9-7 at the break.
An Aled Summerhill try and a fourth penalty from Gareth Anscombe saw Danny Wilson's side extend that lead to 17-7 early in the second half, before the Ospreys roared back via a brace of tries from South African wing, Hanno Dirksen.
And although Josh Navidi's five-pointer briefly put Cardiff back in front on the hour-mark, further tries from Rhys Webb (2) and Sam Underhill secured a victory for the Ospreys which keeps their slim play-off hopes alive while ending those of their opponents.
In further bad news for the Blues, flanker Sam Warburton was forced off in the first half with a shoulder problem.
The Wales skipper has suffered several serious shoulder injuries in the past and coach Wilson confirmed that the 27-year-old will be assessed overnight.