Ulster escaped from the Stadio Monigo with a 24-20 victory, after a second-half onslaught from Benetton Treviso saw the Italian side come within a whisker of turning the game on its head.
First-half tries from Paddy Jackson, Ruan Pienaar and Tommy Bowe gave Ulster a 24-0 lead with less than 30 minutes played, but Sam Christie collected Jayden Hayward's kick for the first of 20 unanswered points for the hosts just before half-time.
Francesco Minto also went over the other side of the interval, but despite Hayward's efforts with the boot, the hosts couldn't find the killer blow as Ulster clung on to claim the victory.
Meanwhile in the other Sunday fixture, a stellar performance off the kicking tee from Dan Biggar helped Ospreys back to the GUINNESS PRO12 summit.
Biggar was also the architect as Tyler Ardron finished in the left corner for Ospreys' only try as they saw off Newport Gwent Dragons 22-11, and replacement Richie Rees' late score was not enough to haul his side back into the contest.
But both Glasgow Warriors and Munster kept up the pace with the league leaders and recorded convincing victories.
Alex Dunbar, Peter Murchie and DTH van der Merwe chipped in with tries while Niko Matawalu produced a sparkling display at scrum-half to ensure Glasgow recorded their 15th consecutive GUINNESS PRO12 victory at Scotstoun, beating Scarlets 22-7.
And Munster side-stepped a potential banana skin to roll over Zebre 31-7 in Italy, thanks to first-half tries from Felix Jones, CJ Stander and Conor Murray, before Simon Zebo touched down early after the break to put the game to bed.
But it was not all good news for the Irish sides as Connacht's unbeaten record at the Sportsground was shattered when they went down 16-13 to Edinburgh in a GUINNESS PRO12 Friday night thriller.
Pat Lam's side had not lost at home all season, but were foiled by a kicking master-class from Sam Hidalgo-Clyne, who overcame the treacherous conditions to slot home three second-half penalties that made the difference.
And Leinster stayed fourth in the table with a bonus-point victory at Cardiff Blues, where scores from Noel Reid, Luke McGrath, Tadhg Furlong and the returning Jimmy Gopperth saw the Boys in Blue to a 22-13 win.
TRY OF THE WEEKEND
With the game all but won in Italy, Munster produced a moment of magic that saw Simon Zebo go over under the posts for a bonus-point try.
Zebre's first attack of the second-half was broken down, and after CJ Stander handed the ball on to Ronan O'Mahony, the winger's perfectly placed kick infield was collected by Zebo who raced through and dotted the ball down.
BREAK OF THE WEEKEND
Liam Williams brought Scarlets roaring back into their game against Glasgow Warriors with a superb break to steal the lead before half-time.
A loose pass from Matawalu was intercepted and Aled Davies found Williams, who picked his line and broke through the Warriors defence.
The full-back then showed great strength to see off two Glasgow tackles and charge over for a sensational try.
PLAY OF THE WEEKEND
Jimmy Gopperth ensured Leinster made a lightning start to their game at Cardiff Blues, as he spotted a gap at a ruck and raced through with just a minute on the clock.
The fly-half burst through on his own ten-metre line, and expertly drew two tackles before offloading a reverse pass to Noel Reid to complete the score.
PLAYER OF THE WEEKEND
While Niko Matawalu shone at Scotstoun, the performance of the weekend belonged to Ospreys' Dan Biggar who undeniably made the difference against Newport.
The fly-half was flawless with the boot, kicking six from six for 17 points, as his side bounced back from defeat to Scarlets in their previous game.
Biggar also had a hand in Ardron's try, as Ospreys recycled the ball well from the breakdown, and added the extras himself from the touchline to put the Swansea side in the driving seat.
Follow us on Facebook, join the conversation on Twitter, sign up to our YouTube channel for extensive match highlights and sign up for our newsletter for regular updates on the GUINNESS PRO12.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland