|Ulster (10) 30|
|Tries: Penatly Try, Payne, Jackson Cons: Jackson 2, Marshall Pens: Jackson 3|
|Leinster (6) 6|
|Pens: Sexton 2|
Paddy Jackson scored 18 points as Ulster strengthened their grip on a Pro12 play-off place with a comprehensive victory against Leinster.
A penalty try helped the hosts lead 10-6 at the break before Jared Payne and Jackson crossed in the second half.
Rob Kearney and Luke Fitzgerald were sin-binned for Leinster, who failed to score in the second period.
The win guarantees Ulster a European Champions Cup place ahead of their final Pro12 game against the Ospreys.
Despite the emphatic defeat, Leinster remain in third and could still secure a home semi-final if second-placed Connacht slip up against Glasgow in next weekend's final round of games.
Ulster were forced to make a late change to the starting team with Craig Gilroy ruled out with a virus and replaced by Rory Scholes.
Ulster seize control
The home side started brightly with Jackson nailing a 12th minute penalty after obstruction on Andrew Trimble.
Ulster grew in ascendancy, moving the big Leinster pack around the pitch, and converted their dominance into points when Ruan Pienaar engineered the opening try.
He spotted a hole in Leinster's midfield, burst through the gap and launched a kick-chase before being clattered illegally by Rob Kearney after 18 minutes.
The Irish full-back was sin-binned for the cynical body-check which denied Pienaar a certain try and referee George Clancy awarded Ulster a penalty try, which Jackson converted.
With a 10-0 lead and Leinster down to 14 men, Ulster had the opportunity to press home their advantage but instead it was the visitors who seized the momentum.
Leinster close gap
With Rhys Ruddock influential and Sexton pulling the strings, they worked their way into the game.
Leinster outscored Ulster 3-0 while Kearney was in the sin-bin, Sexton landing a difficult sideline penalty attempt in the 28th minute and he scored again to reduce Ulster's interval lead to 10-6.
Fitzgerald, part of a Leinster quadruple substitution early in the second half, was only on the pitch two minutes when he was sin-binned for holding Scholes' arm as he tried to collect a Stuart McCloskey pass.
Ulster ended a 35-minute scoring drought through Jackson's penalty to move 13-6 ahead.
Having failed to take advantage of Kearney's sin-binning, Ulster were more clinical with the extra man this time with Jared Payne scoring a 58th minute try.
After a lineout maul, Luke Marshall's fast hands deftly switched the play and Payne made the numerical advantage count by crossing over out wide.
Man-of-the-match Jackson added a penalty and a breakaway try, intercepting Eoin Reddan's misplaced pass, to wrap up a convincing victory for Ulster.
Ulster: J Payne; A Trimble, L Marshall, S McCloskey, R Scholes; P Jackson, R Pienaar; C Black, R Best, R Lutton; P Browne, F van der Merwe; I Henderson, C Henry, S Reidy.
Replacements: R Herring, K McCall, A Warwick, R Diack, R Wilson, P Marshall, S Olding, D Cave.
Leinster: R Kearney; I Nacewa, G Ringrose, B Te'o, D Kearney; J Sexton, L McGrath; J McGrath, R Strauss, T Furlong; D Toner, H Triggs; R Ruddock, J van der Flier, J Heaslip.
Replacements: S Cronin, P Dooley, M Ross, M Kearney, J Murphy, E Reddan, I Madigan, L Fitzgerald.
Referee: George Clancy (IRFU).