Wales scrum-half Rhys Webb made a successful return from injury as the Ospreys won 21-17 to become the first team to beat Munster in Cork since January 2013.
Munster had won 12 games on the bounce at Irish Independent Park since a loss to Cardiff Blues over three years ago, but Owen Watkin's first regional try and 16 points from man-of-the-match Sam Davies guided the Ospreys to a hard-earned Guinness PRO12victory.
Three tries were scored in an entertaining and evenly-balanced first half, Duncan Williams' charge-down effort for Munster and a tremendous first score in red by Francis Saili sandwiching Davies' 24th-minute touchdown.
A Davies penalty cut the gap to 12-10 by half-time and while Munster replacement Robin Copeland went over to put seven points between the sides, Webb's introduction for his first appearance in five months, coupled with Watkin's touchdown and two more Davies penalties, saw Steve Tandy's men finish on top.
In Saturday's action, Cardiff saw their PRO12 winning streak come to a shock end in Italy as rock-bottom Benetton Treviso claimed their first victory of the season.
A Cardiff win would have been their fifth on the trot and made it their best run in the competition since 2010, but they surprisingly came unstuck 13-7 against a Treviso side who had lost all 13 of their matches this term.
In fact, the last time that Treviso had tasted PRO12 success was on February 20, 2015, when they beat Cardiff on home soil.
And the Italian side proved to have Cardiff's measure once again at the Stadio Comunale di Monigo, running out victors thanks to a penalty try and eight points from the boot of Jayden Hayward.
In reply, the Blues were only able to get on the scoresheet through Blaine Scully's first-half try and the conversion from Rhys Patchell.
Ulster notched up their third consecutive PRO12 win to keep them set for a top-four finish as they just about overcame Glasgow Warriors 13-10 at a damp Kingspan Stadium.
It took a second-half try from Callum Black -- on the prop's 100th appearance which also brought his first score -- to give Ulster the lead for the first time after they had trailed 5-3 at the break.
Replacement Paddy Jackson's conversion followed by a penalty -- Ulster's only score of the first half had come from a Ruan Pienaar penalty -- gave the home side their hard-earned victory.
But the reigning champions -- without a win in the league since last November -- snatched a late losing bonus point through an 80th-minute try from sub Taqele Naiyaravoro which came despite the fact that Gregor Townsend's men were down to 14-men.
In Llanelli, the Scarlets were made to weather a late fight back from Edinburgh before Aled Thomas' penalty secured a crucial 22-21 victory for the hosts.
Morgan Allen's early try, converted by Steve Shingler, combined with one penalty from Shingler and a further three from Thomas had put Scarlets 19-6 up after 53 minutes.
However, tries from Cornell du Preez and Alex Toolis narrowed the deficit before a 66th-minute Greig Tonks penalty put Edinburgh in front.
The hosts rallied, though, with Thomas' late penalty securing a win that keeps them fourth, level on points with Leinster.
Elsewhere on Friday, Leinster ran in eight tries to maintain their push for a play-off place with a 52-0 victory over Zebre at the RDS.
New Zealander Hayden Triggs and academy player Adam Byrne claimed their first tries at senior level for the hosts, and thanks to further efforts from club captain Isa Nacewa and Luke McGrath, Leinster had the bonus point in the bag by half-time leading 26-0.
Leo Cullen unloaded his bench upon the resumption and Jordi Murphy, Sean Cronin, Garry Ringrose and Cian Kelleher shared out four more tries as the Irish province comfortably recorded their 10th league triumph of the current campaign.
Connacht briefly returned to the top on Thursday night as they came from behind to earn a bonus point in an entertaining match at Newport Gwent Dragons.
First-half tries from wing Matt Healy and fullback Tiernan O'Halloran and touchdowns after the interval from No.8 Eoghan Masterson and centre Bundee Aki, plus three Craig Ronaldson conversions, saw Connacht home.
The Welshmen led 21-14 going into the last 12 minutes after centre Adam Hughes and wing Ashton Hewitt crossed the Connacht line, while fly-half Jason Tovey landed a penalty and his replacement Angus O'Brien booted a conversion and two penalties.
Connacht are now four points clear of second-placed Ulster -- who host Glasgow on Friday night -- and five in front of the Scarlets, who face Edinburgh.