In a tight match at the Liberty Stadium, the English Premiership side edged the game and came away with the vital victory.
It was Saracens who opened the scoring with centre Owen Farrell kicking his first penalty after four minutes.
Dan Biggar responded for the hosts with his first shot at goal sailing over after 12 minutes. Farrell and Biggar then exchanged further penalties before an Ospreys error handed Saracens the lead.
Straight from the re-start Biggar was charged down near his own line as he tried to clear and Saracens number 8 Ernst Joubert crossed for the game’s first try.
Farrell converted and then kicked his third of the half to take the scores to 16-6 in his side’s favour at the break.
The hosts had two early second-half chances to narrow the deficit but Biggar was off target with an early penalty attempt and then the Ospreys had Ashley Beck held up over the line.
It was an evenly matched second period and the Ospreys finally broke through the Saracens line after 66 minutes with Ian Gough touching down. Biggar’s touchline conversion brought the scores to within three.
The Ospreys couldn’t find a way through at the death but did come away with a losing bonus-point.
The defeat leaves the Ospreys in third in Pool 5 after four games and will welcome Benetton Treviso to the Liberty Stadium and travel to Biarritz in their final two games in January.
