Second-half tries from Sam Tuitupou and Barry Murphy proved crucial for Munster as they were pushed all the way by the Scarlets in their 27-26 win at Musgrave Park.
Inspirational captain Jonathan Edwards helped himself to a brace of tries and Rhys Priestland kicked six of his eight shots at goal to give the Scarlets a chance of winning the top-of-the-table clash.
But quickfire scores from Tuitupou and Murphy, despite having Peter O'Mahony in the sin bin, supplemented by Paul Warwick's 17-point haul, guided Munster to a narrow win and a seven-point lead at the summit of the Magners League.
The Scarlets dictated the early exchanges, but Warwick nipped in under the posts for the game's first try.
The Scarlets hit back on the stroke of half-time as Edwards went over, with the extras added, for a 13-13 interval scoreline.
Munster hit back through Tuitupou and Murphy to take a 27-16 lead in the second period, as the home side then held out against the resurgent Scarlets, who scored 10 unanswered points.
Ulster secured their first bonus-point win of the season thanks to a superb second-half comeback in Cardiff to triumph 37-15. Tries from Casey Laulala and Tom James helped the Blues to a deserved 15-8 lead at the break, with debutant Craig Gilroy going over for the visitors.
Gilroy sparked the fightback with a 58th minute touchdown and Willie Faloon, Adam D'Arcy and Paddy Wallace added further tries.
The win takes Ulster up to third and above fourth-placed Cardiff.