Ulster made it a rare double over Leinster after beating the reigning URC champions 18-13 on a rain-swept night in Belfast which brought the top two teams in the league together for this rearranged fixture.
First-half tries from Sam Carter and Michael Lowry ensured Ulster earned themselves the four points, and their first home and away wins over Leinster since 2013, with Nathan Doak kicking a conversion and penalty.
Max Deegan scored Leinster's try, with Ross Byrne converting and adding two penalties, his second being the only score of the entire second half, the losing bonus point keeping the champions top of the table.
After eight minutes, Carter scored close in to the line to get the home side moving, with Doak converting.
Byrne narrowed UIster's lead through a penalty four minutes later.
With the visitors looking more composed, Leinster scored next after two penalties led to pick and goes on the Ulster line with Deegan eventually scoring near the posts, allowing Byrne convert.
The scores then ended up tied with a Doak penalty on 31 minutes.
Ulster were back in the lead shortly afterwards when Lowry and Robert Baloucoune combined with Lowry impressively surging through for an unconverted score.
The half ended with Doak going for goal after Leinster were penalised at a breakdown, with the scrum-half slotting the kick to give Ulster an 18-10 half-time lead.
Byrne slotted his second penalty of the game just one minute after the restart to cut Ulster's lead to five points.
After that, Leinster managed to put themselves into scoring positions on several occasions but big tackles from Baloucoune and Billy Burns helped Ulster keep their line intact.
Ulster: Mike Lowry; Robert Baloucoune, Stewart Moore, Stuart McCloskey, Craig Gilroy; Billy Burns, Nathan Doak; Andrew Warwick, John Andrew, Marty Moore; Alan O'Connor (capt.), Sam Carter; Marcus Rea, Nick Timoney, Duane Vermeulen.
Replacements: Tom Stewart, Eric O’Sullivan, Gareth Milasinovich, Mick Kearney, Jordi Murphy, John Cooney, Ian Madigan, Ben Moxham.
Leinster: Jimmy O'Brien; Adam Byrne, Rory O'Loughlin, Jamie Osborne, Tommy O'Brien; Ross Byrne, Luke McGrath; Peter Dooley, James Tracy, Michael Ala'alatoa, Ross Molony, Joe McCarthy, Rhys Ruddock, Scott Penny, Max Deegan
Replacements: Seán Cronin, Temi Lasisi, Thomas Clarkson, Devin Toner, Dan Leavy, Nick McCarthy, David Hawkshaw, Martin Moloney.
