Saracens took their Heineken Cup record to three wins when they beat the Ospreys 13-16 in Pool 5 at the Liberty Stadium on Friday night.
The result means that Saracens ended the Ospreys' six year unbeaten record in the Heineken Cup.
Ernst Joubert's opportunist first-half try and 11 points from the boot of Owen Farrell proved enough to claim victory for the English Champions.
Farrell and Dan Biggar traded early penalties in a tight opening before Ospreys fly-half Biggar saw his clearance kick charged down by Charlie Hodgson, setting up Joubert for the game's opening try.
Farrell had no problems with the conversion and he then kicked a further penalty for Saracens before the break.
Ashley Beck twice went close as Ospreys rallied early in the second half before former Wales lock Ian Gough touched down for his first European try, Biggar converted to narrow the lead the three points with 15 minutes remaining.
However Heineken Cup winner Peter Stringer used all his experience from countless campaigns with Munster to help Saracens close out the game, and with it a crucial win.
Final Score Ospreys 13 (6) Saracens 16 (16)
Try - I Gough
Conversion - D Biggar
Penalty - D Biggar (2)
Yellow Card - P James (39)
Try - E Joubert
Conversion - O Farrell
Penalty - O Farrell (3)
Yellow Cards - S Brits (51), K Brown (64)
Man of the Match: Jacques Burger (Saracens)
Referee: Jerome Garces (France)
Ospreys: R Fussell (H Dirksen 56); T Bowe, A Bishop, A Beck, S Williams; D Biggar (M Morgan 76), R Webb (K Fotualii 51); P James (D Jones 57), R Hibbard, A Jones, I Gough, I Evans (J Bearman 71), R Jones, J Tipuric [capt] (G Stowers 76), J Thomas
Saracens: A Goode; D Strettle, O Farrell, B Barritt, C Wyles (J Short 51); C Hodgson (A Powell 72), B Spencer (P Stringer 62); R Gill, S Brits (J Smit 72), M Stevens (C Nieto 62), S Borthwick [capt] (G Kruis 71), M Botha, K Brown, J Burger (A Saull 71), E Joubert (J Smit 55)
With thanks ERCrugby.