Despite a battling performance in tricky windy conditions at Ormond Park, Ulster were left to rue a few missed opportunities in the Munster 22 and some ill discipline in moments.
Munster started on the front foot and Ulster defended well in the early moments, with captain Ethan McIlroy making a good covering tackle into touch.
In an early blow, Ulster centre Ben Carson was shown a yellow card for a tip tackle with Munster on the attack. A couple of minutes later the home side made their man advantage count and Sean O'Brien went over on the right flank. Butler's conversion was unsuccessful.
Ulster then had to reshuffle the front row, after Flynn Longstaff suffered an injury after only 14 minutes, with fellow Academy prop Tom McAllister replacing him at tighthead.
In the swirling wind, both sides fought for territory and possession, with Munster's experienced back row, John Hodnett, causing issues around the breakdown before he too had to be withdrawn due to injury.
Ulster were left kicking themselves for Munster's second score. With Ulster launching an attack into the Munster 22, a pass went loose as Munster's scrum-half Jake O’Riordan was able to make a break clear into the Ulster half. The nine looked to his left and had Ben O'Connor for support. The full-back was able run the ball in for the home side's second try. Butler wasn't to be denied this time with the conversion for a 12-0 lead.
Ulster regathered themselves and went to the corner after a penalty. As the lineout maul drove towards the Munster line, the referee blew for an offside joining and the opportunity went to waste.
A great line break from Ben Carson saw Ulster advance into Munster's 22 and Ulster were working the ball well in the attack.
However in another frustrating moment the attack was broken down after the referee adjudged Carson was crossing between an attacking pass.
With another opportunity going amiss, the referee blew for half time and Munster took a 12-0 lead into the interval.
Determined to force themselves back into the match, Ulster began the half on the front foot, with strong carries from hooker James McCormick and Wilhelm De Klerk getting Ulster good territory.
Ulster made their breakthrough in a well-worked attack. The ball was worked through the hands and Academy back Jonny Scott was found on the left wing. Scott carried well and was able to make a smart offload to back rower, James McKillop, who made no mistake as he dived over to score. Flannery's conversion kick edged wide in the breeze, leaving the scoreline at 12-5.
Munster increased their intensity after the score, with Ulster's Tom McAllister and Jonny Scott making important defensive efforts with the home side pressing forward.
In the 56th minute, Munster stretched their lead, after hooker Max Clein was able to peel away from the back of a lineout maul and go over for their third try, with Butler converting.
Munster were effective from their attacking maul, and used their forward power for their fourth try of the afternoon in the 65th minute. This time it was replacement hooker, Danny Sheahan, who was able to pick and go from close range despite Ulster's hard work in defence on their goal line.
With a raft of changes from the bench, Ulster continued to battle but struggled to get a foothold in the final quarter. With the clock in the red and Ulster on the attack, they received a further blow when replacement hooker Henry Walker and centre Wilhelm De Klerk were both shown yellow cards for their involvement in a tip tackle.
Munster sensing blood launched another late attack at the death and Ulster's 13 players tried to halt the late score before another yellow card offence.
Try scorer James McKillop was shown a yellow card and Munster found the space against the 12 players for Danny Sheahan to score his second. Butler's conversion was wide and that brought the final whistle.
Ulster 'A' will have the chance for a quick reaction, with both teams facing each other in Round 4 at Affidea Stadium on Friday 20th February.
FT: 31-5
Scorers
Munster 'A':
TRY: O'Brien, O'Connor, Clein, Sheahan (2)
CON: Butler (3)
Ulster 'A':
TRY: McKillop
FT Reaction: Ethan McIlroy
"A tough match. Munster put it up to us early on and maybe we didn't quite get our game plan right with playing into shapes on a really windy afternoon which made conditions tough. We battled in the second half, a few things out there maybe didn't go our way and if we cleaned up a few inaccuracies, maybe the score could have been different. We'll take a lot from this game and bring it into our match next week.
We'll gather ourselves, review the match and go again."
Teams
Ulster A:
1.Callum Reid, 2. James McCormick, 3. Flynn Longstaff, 4. Joe Hopes, 5. Paddy Woods, 6. James McKillop, 7. Tom Brigg, 8. Lorcan McLoughlin, 9. Conor McKee, 10. Jake Flannery, 11. Ben Moxham, 12. Ben Carson, 13. Wilhelm De Klerk, 14. Jonathan Scott, 15. Ethan McIlroy (Capt)
Replacements:
16\. Henry Walker, 17. Jacob Boyd, 18. Tom McAllister, 19. Ben Moore, 20. Noah Bell, 21. Clark Logan, 22. James Humphreys, 23. Owen O’Kane, 24. Jon Rodgers
Munster A:
(15-9) Ben O’Connor (UCC); Andrew Smith (Young Munster), Fionn Gibbons (Young Munster), Seán O’Brien (Nenagh Ormond), Shay McCarthy (Young Munster); Tony Butler (Young Munster), Jake O’Riordan (Young Munster);
(1-8) Mark Donnelly (Cork Constitution), Max Clein (Garryowen), Ronan Foxe (Garryowen); Evan O’Connell (Young Munster) (C), Conor Ryan (UCC); Michael Foy (Cork Constitution), John Hodnett (UCC), Ruadhán Quinn (Young Munster).
Replacements: Danny Sheahan (Cork Constitution), George Hadden (Garryowen), Kieran Ryan (Young Munster), Conor Kennelly (Highfield), Seán Edogbo (UCC), Rory Woods (Garryowen), Paddy Patterson (Cork Constitution), Dylan Hicks (Cork Constitution), Eoghan Smyth (Cork Constitution), Gene O’Leary Kareem (UCC).