Following the Ospreys historic win at Thomond Park on Saturday evening, Ulster's 37-25 win in Edinburgh on Sunday guarantees the region's place in the end of season play-offs.
With just one match remaining in the regular Magners League season, when the Newport Gwent Dragons visit the Liberty Stadium on the weekend of 7/8/9 May, the Ospreys are in the driving seat to secure a home semi-final the following weekend.
Current league leaders Leinster have also secured their play-off berth, with Glasgow in third place likely to progress, while the fourth and fifth placed sides Munster and Cardiff Blues clash at the Cardiff City Stadium to fight for the final slot.
Ospreys Managing Director, Roger Blyth said:
"The introduction of the play-off system to the Magners League this season has been a huge success, really increasing the excitement in the competition and keeping it alive right up until the final weeks of the campaign.
"Thanks to our outstanding win at Munster on Saturday, coupled with results elsewhere, we have now secured our place in the play-offs, and are really looking forward to the semi-finals. The squad have bounced back from the disappointment of the Biarritz match in spectacular fashion. They showed great spirit to front up for three difficult games in Ireland, and to come away with two wins and a losing bonus point is a measure of not only the ability of the squad, but the character and resolve as well. The coaching team and the playing squad should be congratulated on that, I don't think we should underestimate the size of their achievement over the last two weeks.
"Before we focus on the semis though, we have to face the Dragons next week. Although we will be looking for the win that will guarantee a home semi, we realise that it isn't going to be straightforward and we will have to replicate the form we've shown in recent weeks if we are going to succeed.
"I would expect that it's going to be a great rugby occasion, we should have a good crowd present and there'll be plenty of end of season drama - exactly what the play-offs were introduced for. I'd like to think that our supporters will turn out in big numbers once again to give us that edge to secure the home semi-final, setting up another memorable day for the Ospreys."