Ulster are set to meet Provincial rivals Connacht in the Guinness PRO14 semi-final qualifier next month.
Connacht defeated Cardiff Blues 29-22 in a nervy encounter in Galway on Saturday afternoon to secure third place in Conference A.
The Blues had to win to set up a three-way battle on April 27 with Connacht and Ospreys to the final play-off place and a European Champions Cup place next season.
However, Connacht ensured all four Irish Provinces would compete in Europe next season as well as challenge for the PRO14 title, Leinster and Munster having already secured their places, as they took all five match points at The Sportsground.
Caolin Blade and Gavin Thornbury crossed for tries in the first half, Jack Carty converting both to give the hosts a 14-7 lead at the break, Cradiff responding with a Owen Lane try and Gareth Anscombe converstion.
Carty and Anscombe exchanged penalties either side of a Carty converted try to leave Connacht 22-7 in front.
Josh Turnbull’s try and Anscombe’s conversion put seven points between the sides but Matt Healy crossed to secure a bonus point for Connacht.
But The Blues hit back again with a 79th minute try through Jason Harries to leave seven points between the sides and leave a nervous finish for the hosts.
But Cardiff survived a tense four minutes of added time to secure the win.