The victory over the Heineken Cup champions allowed Glasgow Warriors to sneak back into the play-off places at the expense of Joe Schmidt's men by a point as they came out on top in an 1872 Cup derby against Edinburgh 23-14.
On a weekend where every fixture was a derby between teams from the same country, Zebre are still without a victory this season as Benetton Treviso edged them out 10-3.
Connacht were left devastated as feverish defence from Munster meant there was no score in the final 27 minutes of their game at the Sportsground - the match ending 16-12 to Munster.
And Scarlets came away from the Cardiff Arms Park with the win against Cardiff Blues 9-6 in difficult conditions.
TRY OF THE WEEKEND
Ulster's third and final try against Leinster, scored by Andrew Trimble, was all about the vision of South African Ruan Pienaar.
After some typically excellent work from the Ulster pack had pushed their side up the field Pienaar collected the ball and produced a beautiful cross-field kick to Trimble who collected, cut inside and scored.
Ulster might be without the services of British and Irish Lions winger Tommy Bowe for the foreseeable future, but in Trimble and Craig Gilroy they appear to have a couple of handy replacements on the wing.
BREAK OF THE WEEKEND
Wet conditions made a running game particularly tricky in Cardiff's game against Scarlets which made George North's late dash all the more impressive.
As the final quarter of the game arrived, neither side had managed to string a consistent play together so the 20-year-old decided to go it alone.
North picked the ball up in the opposition half and burst deep into the heart of the defence and was only brought down five metres out.
PLAY OF THE WEEKEND
Connacht thought a try was a certainty when rampaging winger Fetu'u Vainikolo showed great foresight to intercept Johne Murphy's pass to streak away.
But with the try-line beckoning, Munster fly-half Ian Keatley turned on the gas to not only catch up with Vainikolo but then produce a brilliant challenge to drag him out of play and end the danger. Fantastic rugby both attacking and defensively.
PLAYER OF THE WEEKEND
In as tight a game as Connacht's clash with Munster was, an accurate boot will often prove absolutely vital but in Keatley's case he also saved a certain try.
A four-point win proved how tough the evening was for Munster and with Keatley scoring 11 of his side's 16 points it was a dazzling display with the boot.
But chalk up another seven to the Irishman's name due to his fantastic last-ditch challenge to stop Vainikolo going over the whitewash.
LIONS WATCH
The Ulster front row continues to dominate and despite falling out ofIreland contention recently Tom Court was superb at prop alongside Rory Best, who will be a strong contender for the hooker's job in Australia.
If Court can continue to impress enough to make it into the Six Nations squad he could come into contention to battle for a place on the front row to continue his fine partnership with Best.
And Welshman North looked a cut above as conditions hampered the Cardiff match against Scarlets - the 20-year-old managing to burst through the Blues defence in a tense game.
Elsewhere Scotland lock Al Kellock scooped the man-of-the-match award in Glasgow's 1872 Cup success over Edinburgh, showing once more how influential he can be in the second row and as a leader.
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