With little more than an hour before kick-off on Friday evening, Priestland was still stuck in M4 traffic.
However he arrived at Parc y Scarlets in the nick of time and went on lead Scarlets to a 19-9 victory over a Glasgow side who had previously lost just once this GUINNESS PRO12 campaign.
And Pivac was delighted to be able to call on Priestland, admitting his kicking game is crucial in getting the Scarlets ticking.
"There was some sort of accident on the M4 and Rhys couldn't get here," Pivac said. "It took him two and a half hours to get here from Cardiff so basically he threw his kit on and went straight into the warm-up.
"He felt his knee early on, but played through that and I thought he went very well. He has come back here and been positive.
"He knew he didn't play as well as he would have liked in the game against Fiji, but he was fine and he wanted to go out and perform well for us and I thought he did that.
"Rhys does a good job for us. He has a big kicking game, gets our backline under way and when he is in a run of form he is as good as anybody around. We are pleased to have him."
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