Young fly-half Matthew Jones scored a match-winning 18 points, including a last-minute try that provided the game's only exciting moment. Ospreys winger Stefan Terblanche opened the scoring just before the 20-minute mark when he toed the ball ahead and beat opposite number Tyrone Howe in a 30-metre foot-race. Jones slotted the extras and added a monster 48-metre penalty goal that was still rising as it went between the uprights.
Opposite number David Humphreys converted one of a string of penalties to the visitors, but ignored a certain three points when he tapped in front of the posts and kicked to the corner for centre Paul Steinmetz to leap high, but the New Zealander could only help the ball over the sideline.
Ulster prop Rod Moore was sent to the sin-bin for a cynical professional foul, but the Ospreys were having communication problems in the midfield and couldn't take advantage of the one-man advantage. The Irishmen were in touch at only 10-3 down at halftime, before Jones extended his side's lead with a well-struck penalty goal.
Ulster gradually came back into the game - well aware that they were lucky to be only 10 points behind and desperate to make the Ospreys pay for their poor finishing. Replacement fullback Paddy Wallace broke clear before being illegally dragged back by the collar, and Humphreys' second penalty goal bridged the gap to a converted try with 10 minutes to play.
A third Humphreys goal from near the halfway line moved the Ospreys fans to the edge of their seats, but Jones banged one over from point-blank range and scored a last-minute try as the home side held on - despite a late penalty try to the visitors.
Tries - S Terblanche, M Jones
Pens - M Jones 3
Cons - M Jones 2
Try - Penalty try
Pens - D Humphreys 3
Con - D Humphreys
Halftime: Ospreys 10-3
Yellow card: R Moore (Ulster)
Referee: Andrew Ireland (Scotland)