An opportunist close-range try from Filo Tiatia with five minutes remaining got the Welsh region out of jail and puts them seven points behind leaders Munster.
Sean Holley’s men looked down and out at a rain-soaked Ravenhill after Ulster wing Simon Danielli pounced on 65 minutes.
But Tiatia saved the day when the powerhouse number eight struck from close-range to score only his eighth try for the Ospreys in 70 appearances.
Holley made ten changes from the EDF Energy Cup semi-final defeat to Gloucester and rested big hitters Ryan Jones and star wingers Shane Williams and Tommy Bowe with next weekend’s crunch Heineken Cup quarter-final against Munster in mind.
The heavens opened prior to kick-off but the Welsh region moved into a 6-0 point lead inside the opening 16 minutes thanks to two sweetly-struck penalties from James Hook.
But the hosts got a foothold on the game and after flanker Tom Smith was caught offside, Schifcofske capitalised with the penalty from in front of the posts.
The Ospreys rallied but spurned two golden opportunities to increase their slender three-point lead before half-time when James Hook saw his drop goal attempt on 36 minutes drift wide.
Then Gareth Owen made a superb break from full-back to assist Hook and Andrew Bishop before Jonathan Spratt was eased into touch.
Schifcofske miscued two penalty chances after the interval but the Australian full-back showed his mental strength to make it third time lucky three minutes later to level the scores
And the hosts moved ahead for the first time in the match when Danielli beat David Bishop to Niall O’Connor’s cross kick and crash under the posts.
Hook added a third penalty before New Zealander Tiatia pounced to hand the Ospreys a crucial away triumph and keep their title aspirations alive.
