But those hopes were shattered even before the final whistles sounded in Thomond Park and Liberty Stadium.
It’s hard to know which was the bigger disappointment but it’s a disaster either way.
Certainly the worst result was Ospreys losing at home to six tries by Ulster.
That result was never good enough no matter what was resting on the game, and there will be some soul-searching within the squad.
But it’s even more unacceptable when it has cost them a place in the Champions Cup.
It’s hard to imagine the likes of Alan Wyn Jones, Dan Biggar and Rhys Webb playing in the Challenge Cup next season.
These are household names, players people pay good money to watch. They are at the top of their game and want to be competing at the highest level, so to be relegated to the second division of European rugby is a massive blow.
It’s also a blow to the club as a whole because there is a big difference in profile – and revenue – between the two levels of Europe.
The irony is that Ospreys came so close to reaching the quarter-final against all the odds before losing away at Exeter Chiefs in the last round of Pool games in January. Now they’re left with nothing.
I know that will really hurt Steve Tandy their coach and what he does over the summer is massively important as they try to re-establish the club as a force.
It’s also hugely disappointing for the whole of Welsh rugby to have only one team in the Champions Cup next season, the same as Italy.
I can’t imagine Warren Gatland will be too pleased to see so many of his top players facing the likes of Calvisano or Enisei rather than Toulon, Saracens or Racing.
As for the Scarlets, they have thrown away a golden opportunity. They made a blistering start to the Pro 12 season and I thought they could go all the way.
They seemed to have the confidence and attacking style to take the league by storm.
Even a few weeks ago I was still tipping them to win the title. But they hit a slump at exactly the wrong time.
They were unlucky to be infected with a virus before the Glasgow game that left half the squad in no fit state to play the reigning champions.But they blew it against Cardiff Blues and that left them with the one scenario they really didn’t want – having to win in Limerick.
Once Samson Lee and then Scott Williams were ruled out, it was always looking a bridge too far. So it proved.
That defeat has left a major hole in their season.
Wayne Pivac unashamedly banked everything on making the play-offs. You can see from his selections in the Champions Cup that he virtually wrote off Europe as he chased the Pro12 title. But it hasn’t worked.
It has left Wales without a team in the play-offs for the first time and the regions struggling to keep up with Glasgow and particularly the Irish.
Yet again Leinster top the table and must now be favourites after winning more games than any other team in the league. They are also old hands at winning the Celtic title and, crucially, have home advantage in the semi-final against Ulster.
Connacht have been rugby’s answer to Leicester City this season.
Well coached, organised and with a bit of flair from their summer signings, they have been a breath of fresh air this season. They beat Glasgow 14-7 yesterday and they will meet again in Galway in the play-off.
As for the Welsh regions, it’s going to be a tough summer with some hard work and tough talking.
Probably the best-placed team are Cardiff Blues. They have improved as the season has gone on and finished on a high by winning at Edinburgh. They seem to have found a way of playing they are happy with and could be real challengers next season.
But it’s too late to save this season. There’s no silver lining and Welsh regional rugby.