Warren was due to be on the bench but 15 minutes before kick-off captain Gareth Maule pulled up with an injury.
The 20-year-old, who signed a development contract over the summer, duly delivered a man-of-the-match performance with two tries in the Scarlets' 33-17 victory - their first win since the opening weekend of the season.
And Davies was quick to hail the youngster's 'special' talent.
He said: "I wasn't fazed by that because what Adam has got is exceptional pace and with any half chance he will make the most of it which he did and he's very aggressive as well.
"He's somebody we have given a development contract to this year as result of his ability.
"He's got plenty to learn but equally has got something a bit special about him and was outstanding for us tonight."
The victory brought to an end a run of four straight defeats for the Scarlets but Davies is adamant he was not unduly concerned about their poor form.
He added: "This group has been very close to getting a result and I'm pleased for the players because it comes after a lot of hard work and effort which they've made in their approach to every game.
"It's been frustrating for us, but one thing we haven't done is panic, we believed the result would come eventually and it did.
"Another positive is that during this first set of games, a lot of young boys have been blooded again, and they have had their opportunity and played better as a result of this series of games which have been physical and very competitive."
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