Ulster overcame a sluggish start to beat Ospreys 28-24 and become the second Irish province to book their spot in the Challenge Cup quarter-finals.
In difficult conditions caused by Storm Dave, the hosts took an early lead as Cormac Izuchukwu crashed over.
The advantage was cancelled out by Reuben Morgan-Williams' try for Ospreys in the ninth minute, and the scrum-half then sent in Dan Kasende.
Dan Edwards extended their advantage with a penalty and Richie Murphy's side trailed 17-7.
However, Ulster reduced to the deficit in the run-in to half-time, David McCann touched down to leave the margin at three by the interval.
The Irish province took the lead five minutes after the break through Jacob Stockdale before Nick Timoney strode away into the corner for Ulster’s fourth try.
However, they could not take advantage of Jac Morgan’s sin bin and they were down to 14 men themselves with just over 10 minutes remaining after a high tackle from Jack Murphy led to a penalty try, leading to an edgy finale.
There was relief late on as a score which would have given Ospreys the lead was ruled out for a forward pass, Ulster clinging on to win.
They will face off against Ronan O'Gara's La Rochelle in the quarter-final in Belfast next Friday evening. Connacht, meanwhile, are away to Montpellier on Saturday, having overcome the Sharks last night.
Munster bowed out of Europe's second tier competition following a 31-21 loss away to Exeter Chiefs this afternoon.
