It was a nip and tuck affair with the lead chasnging hands on three seperate occasions. However, in the end, two tries in the final quarter for the Ospreys saw them home to a 29-28 victory.
Team manager Graham Court said; "It was yet another cracking game of rugby and a great advert for this competition. Obviously, we understand the disappointment of the Scarlets, but for us, it was the perfect way to finish off the season.
"We knew how difficult it would be because they defeated us twice in the regular season. On this occasion, it looked as though it might be going the same way when they led by 100 points in the second half.
"However, we stayed in there and eventually came out on top. It was a nervous ending in which they had an opportunity to win it with a penalty."
Scarlets team manager Wyn Thomas said; "We are naturslly gutted by the result, but when we look at the season as a whole, I think we can be very proud of what we have achieved.
"We have beaten all five sides and I think the development of our players has been considerable."
A converted try from Andrew Waite edged the Ospreys ahead early in the first half but two penalties from the prodigious Scarlets outside half Jordan Williams cut the deficit to a single point after 20 minutes.
After that, a Sam Davies try put the Ospreys 14-6 to the good before unconverted tries from Williams and Scarlets wing Dylan Morgan saw the pre match favourites into a 16-14 interval lead.
The second half was an equally tense affair with Jake Randall's try and a fine score from Daniel Thomas putting the Scarlets 28-17 to the good as the game moved into the final quarter.
At that juncture, it looked as though the Ospreys would have to settle for second best with the Scarlets running away with it.
However, Randall and Thomas were then sin binned as the pressure grew and buoyed by their numerical advantage, the Ospreys duly took the lead with tries from Lloyd Wilson and full back Rhys Thomas. Davies' conversion edged them in front and though the Scarlets, once they were back to a full complement, threatened in the closing minutes, Williams failed with a long distance penalty and the honours went to the Ospreys.