A superb solo score from fly-half Matthew Morgan handed them the perfect start against Aviva Premiership opposition but the Warriors’ superior experience eventually told.
Worcester dug deep to run out 24-14 winners in testing conditions as they made the most of flanker Sam Lewis’ sinbinning late in the first period.
A 14-point flurry while Lewis was off the field paved the way for the home side to claim their second win of the tournament despite Morgan’s early score which came about as he collected his own clever grubber kick.
Lewis saw yellow for killing the ball close to his own line and Worcester capitalised as Josh Drauniniu crossed twice in quick succession to hand his team a substantial 21-7 advantage just after half time.
A Hanno Dirksen try gave the Ospreys hope with just under half an hour remaining but the wintery weather conditions meant fashioning a way back into the game was always going to be difficult.
Defeat sees the Ospreys finish third in Pool 1 with one win from four fixtures, but the game time garnered by so many young players and a derby-day success against the Dragons last weekend means there are still plenty of positives to take back into domestic action.
