Ulster missed out on the chance to seal their URC play-off spot as they fell to a 26-22 home loss to Glasgow Warriors, who go into the post-season as top seeds.
Richie Murphy's men sit in eighth place and will hope that Munster, one point behind in ninth, fail to pick up any match points when they host the Lions on Saturday night.
Ulster led with just four minutes to play at the Affidea Stadium but Kyle Rowe's try saw the league leaders take the spoils and secure top spot.
Elsewhere, Cardiff beat second-placed Stormers, who are now just two points ahead of Leinster, who welcome the Ospreys to Aviva on Saturday afternoon.
Leo Cullen's men can't overtake Warriors but any win against the Welsh will secure second place.
The Warriors scored the opening try of the game in the eighth minute when Sione Tuipulotu found Stafford McDowall, who broke through a gap and flew in under the posts.
But Ulster managed to turn the game on its head after half an hour as Zac Ward (below) scored in the corner for their first try before he picked an intercept and ran the full length of the field against the run of play for his second of the night to put his side ahead.
However, Glasgow managed to score twice before the break which gave them a nine-point lead at the halfway point, firstly Nathan McBeth managed to just get the ball down before George Horne jumped over the whitewash underneath the sticks.
The hosts once again managed to come from behind and stick their noses in front though as Ethan McIlroy found the whitewash in the corner following a foot race before Jack Murphy finished a breakout try to put them in front.
Ulster were unable to hang on as their opponents regained the lead with four minutes to play, with Rowe going over in the corner after a great pass from Euan Ferrie out wide to give them a bonus-point try and top spot.
