That was despite a dream start when Tandy and Terblanche both went over inside just eight minutes. The Ospreys showed their intent with early breaks from Ryan Jones and Gavin Henson; both players were involved in the opening score.
Jones's line-out sent Cockbain crashing up the middle, Henson twice provided the link before Tandy was shoved over by the full weight of the Ospreys pack.
Moments later and Terblanche profited from a comedy of errors to streak through under the posts from inside his own half. The Ospreys spilled possession in attack but Sale's Stuart Turner was tempted into a rash pass and former Springbok Terblanche caught everyone looking the wrong way. James Hook converted and added a penalty for a 15-0 lead after as many minutes.
Tempers flared and tensions rose: Andy Lloyd and Dean Schofield were binned for fighting and Chabal soon followed for stamping on Tandy as Sale were kept out by some last-ditch defending.
It was not until the fifty-third minute that the Sharks finally broke the Ospreys' resistance. Hook became the fourth player to see yellow for a professional foul after Oriol Ripol lost his footing with the try line at his mercy.
Juan Fernandez Lobbe was far more assured from a cunning set-piece move twenty yards out, splitting a Sale wall to race over untouched. Henson replied with a penalty to nudge the Ospreys ahead but they could not get their hands on the ball for long enough to score those crucial two more tries.
Sale Sharks 7 - Ospreys 18
HT: 0-15 Attendance: 10,662
Sale Sharks: Try - J Fernandez Lobbe. Con - D Larrechea
Ospreys: Tries - S Tandy, S Terblanche. Con - J Hook. Pens - J Hook, G Henson
Man of the match: J Marshall (Ospreys)