Gerhard van den Heever crossed for Munster, who fell off the top of the table following Leinster's win over Glasgow Warriors on Saturday night.
And Jones admitted his side had to produce a backs-to-the-wall performance in the second half to secure victory.
"We played some great stuff in the first half and created some great opportunities to score.
"But we lacked a ruthless edge in the first-half when potentially we could have been two or three scores up.
"On the flip side, we then defended heroically in the second-half.
"Our set-piece held up under some defensive drives and our phase defence was particularly good.
"The week's preparations set us up for a very physical match and we certainly got one.
"It is no mean feat to win against a top-quality Munster side who showed they have been able to hold their nerve at the death in previous fixtures."
Follow us on Facebook, join the conversation on Twitter, sign up to ourYouTube channel for extensive match highlights and sign up to our newsletter for regular updates on the RaboDirect PRO12
Guinness PRO12 Scarlets News
63x46.png){kind=logo}