Ulster gave their top four hopes a huge shot in the arm as they saw off Leinster, winning 30-6 at Kingspan Stadium on Saturday.
The visitors fell to their worst defeat of the season, with their only points coming from the boot of Jonathan Sexton.
An early penalty try was added to by Paddy Jackson and Jared Payne, meaning a win against Ospreys on the final day of the season will ensure their spot in the play-offs.
Jackson put the home side ahead with 12 minutes on the clock, slotting a penalty from distance.
Ulster were then awarded a penalty try just moments later, as Rob Kearney was sent to the sin bin for blocking Ruan Pienaar on his was to claim his own kick and touch down.
Sexton was finally able to get some points on the board for Leinster, as two penalties in quick succession took the score to 10-6 at half-time.
Leinster's afternoon then got a lot tougher as Luke Fitzgerald saw yellow, and with the visitors down to ten men, Jackson slotted a penalty before quick passing through the backs allowed Payne to carry home unchallenged.
Luke Marshall added the extras, before another penalty from Jackson extended Ulster's lead to 17 points.
As Leinster looked to score a consolation try, a fantastic interception from Jackson on his own 22 allowed him to show the defence a clean pair of heels and race home, before replacement Paul Marshall made the score 30-6 at Kingspan Stadium.
Tries: Penalty, Payne, Jackson
Cons: Jackson, L Marshall, P Marshall
Pens: Sexton 2
Ulster: 15 Jared Payne, 14 Andrew Trimble, 13 Luke Marshall, 12 Stuart McCloskey, 11 Craig Gilroy, 10 Paddy Jackson, 9 Ruan Pienaar, 8 Sean Reidy, 7 Chris Henry, 6 Iain Henderson, 5 Franco van der Merwe, 4 Peter Browne, 3 Ricky Lutton, 2 Rory Best (c), 1 Callum Black
Replacements: 16 Rob Herring, 17 Kyle McCall, 18 Andrew Warwick, 19 Robbie Diack, 20 Roger Wilson, 21 Paul Marshall, 22 Stuart Olding, 23 Darren Cave
Leinster: 15 Rob Kearney, 14 Isa Nacewa (c), 13 Garry Ringrose, 12 Ben Te’o, 11 Dave Kearney, 10 Johnny Sexton, 9 Luke McGrath, 8 Jamie Heaslip, 7 Josh van der Flier, 6 Rhys Ruddock, 5 Hayden Triggs, 4 Devin Toner, 3 Tadhg Furlong, 2 Richardt Strauss, 1 Jack McGrath
Replacements: 16 Sean Cronin, 17 Peter Dooley, 18 Mike Ross, 19 Mick Kearney, 20 Jordi Murphy, 21 Eoin Reddan, 22 Ian Madigan, 23 Luke Fitzgerald
Referee: George Clancy (Ireland)
Assistant Referees: Sean Gallagher (Ireland), Leo Colgan (Ireland)
TMO: Seamus Flannery (Ireland)