Lloyd Williams insists there are "reasons to be optimistic" as Wales try to rediscover a winning formula that has deserted them in alarming fashion.
Head coach Pivac has overseen just two victories – against Italy and the Barbarians – since he succeeded Warren Gatland last November.
And it means the pressure has been ramped up ahead of next Saturday's clash against Georgia, with Pivac already confirming a much-changed team for that Nations Cup encounter.
Six Nations champions England then loom large, leaving Wales firmly on the back foot in their attempts to halt a major slump.
"When you are playing one type of rugby for 10 years, it doesn't change overnight, and I think it is realistic to expect a bit of a transition period," said scrum-half Williams, who featured impressively off the bench in Dublin.
"The boys are all confident with how we are trying to play, so it is just a case of getting used to it and bringing it to fruition.
"It wasn't the result we were after, but there were elements of the performance that we can take a lot out of.
"There are reasons to be optimistic. We just need to keep working on the small things, and the bigger picture will take care of itself."
The last time Wales experienced such a run came straight after they won a Grand Slam, but they turned it around quickly enough to successfully defend the Six Nations title in 2013.
Whether Pivac can summon such a revival in this season's Six Nations, which begins for Wales against Ireland on February 7, remains to be seen.
But it looks unlikely on current evidence, with Wales' fourth successive loss to Ireland also their heaviest in the fixture for six years.
Wales captain Alun Wyn Jones said: "We are not scoring enough points. We also can't shy away from the fact we regressed in the set-piece. It's difficult when you don't have the ball.
"I have been through a couple of periods like this in the past.
"You don't want to learn on the job, but we will have to now. The learning curve is always there, but now it has got steeper."
Pivac added: "It's very frustrating that the changes we have wanted to make have taken time. Under pressure, we are making some errors that are uncharacteristic for some players.
"We will go away and have a look at this game, as we do every game, but we have a few games to look at now for any patterns emerging in terms of individuals making errors.
"The players are working very, very hard. From our point of view, it's roll your sleeves up on Monday.
"We are not going to change from our plans, so there will be a lot of changes for next week, which are already pre-planned.
"And that is to give the squad a run by the end of the Georgia game, and that's what we will be doing. We will continue to build the depth and continue to work hard."