Aironi 11 Ospreys 18
The Ospreys will play Munster in the RaboDirect Pro12 play-offs at the Liberty Stadium after defeating Aironi 18-11.
In an entertaining opening period, the Welsh region took a 15-11 half-time lead thanks to Richard Fussell and Hanno Dirksen tries, with Dan Biggar adding a penalty and a conversion.
The hosts' response came through a Nick Williams touchdown and two Naas Olivier penalties.
But in Aironi's final game before they are disbanded, their fate was sealed with Biggar's second half three-pointer.
With their home semi-final already secure and no chance of catching league leaders Leinster, the Ospreys effectively had nothing to play for.
However, they started this encounter with intent and were rewarded when Fussell touched down after five minutes.
Olivier reduced the arrears with a penalty, but Biggar converted one of his own to take the score to 8-3.
Williams then powered across the whitewash to level the match, but their fly-half failed with the conversion attempt.
The visitors were always dangerous with ball in hand and, after Kahn Fotuali'i had broken the Aironi gainline, Dirksen was on hand to finish off.
After the open nature of the first half, the second, by contrast, was dominated by the set-piece.
And from numerous scrum collapses close to their own line, it was no surprise to see Lorenzo Romano sin-binned for the hosts.
The Ospreys extended their lead to seven points through a Biggar penalty before Tom Smith received a yellow card for the visitors, but Aironi failed to capitalise on the man advantage and the game petered out.