Two more O'Gara penalties after the break kept Munster ahead despite kicks from Priestland and Stephen Jones and Tony McGahan's men held on for the win.
But despite the defeat Davies remains confident that his side has what it takes to dispose of the defending RaboDirect PRO12 champions when the two sides meet again next weekend.
"We weren't accurate enough and we had a couple of chances in the first 20 minutes we weren't sharp enough at taking," he said.
"We were very confident but we weren't accurate enough. This match was of Test-level intensity and you can't afford errors but there were too many in our game.
"But we have always seen this as a two-match series and we have to go out there and get something from the game.
"It's a tough place to go but we will go there all guns blazing as we did against Northampton. We have got the team to beat them."
Elsewhere RaboDirect PRO12 high flyers Ospreys left it too late against Premiership champions Saracens as they lost 31-26.
Chris Wyles' try midway through the second half looked to have put Sarries out of sight at 28-16 but the Welsh outfit rallied late on.
A second Ashley Beck try coupled with the boot of Dan Biggar meant that Scott Johnson's men finished with a losing bonus point.
Connacht went down 14-10 at home to Gloucester, full back Gavin Duffy crossing for the Irish outfit's solitary try in the first half.
Meanwhile, Treviso caused one of the upsets of the round though when they took down Heineken Cup powerhouses Biarritz 30-26 to preserve their unbeaten home record in this year's competition.
Kris Burton added 16 points with the boot while the tries came from Michele Rizzo, Robert Barbieri and Cornelius van Zyl.
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