The Irish province scored a 16-3 win over the Scarlets on Friday night with Paul Steinmetz scoring all 16 points. That defeat consigned the Scarlets to fifth place in the table - and an away draw against the Dragons in the quarter finals after the Newport based side scored a 24-19 win over Connacht to finish fourth - four points ahead of the Scarlets.
Defeat for the men from the West of Ireland means that the Blues, who ran in five tries in their 33-12 win over the Borders, have a Heineken Cup lifeline and will play-off against an Italian side for the final place in the elite European competition.
The weekend's final two games saw Irish wins, Leinster scoring a 30-23 win in Glasgow - with David Holwell pitching in with 15 points, while Munster maintained their unbeaten home record (the only side in the league to remain unbeaten at home all season) with a 30-20 win over Edinburgh. Denis Leamy scoring two of the provinces five tries.
THE CELTIC CUP QUARTER-FINAL LINEUP
(1) Ospreys v Ulster (8)
(2) Munster v Edinburgh (7)
(3) Leinster v Glasgow (6)
(4) Dragons v Scarlets (5)
The games will be played over the weekend of 29/30 April & 1 May. Further details will be released on Monday.