The under-23 duo have both been named in Benitez's squad for the Premier League trip to Fulham, in what represents their first involvement at first-team level.
And with staff at St James's Park having high hopes for the pair, we take a look at the Newcastle United youngsters:
The 19-year-old has enjoyed a difficult campaign, but has seen his hard work in recent weeks rewarded with a place in the first team squad.
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A Newcastle native, Cass missed the early parts of the season due to a troublesome ankle injury, and wasn't reintroduced to under-23 football until February.
But since then, the defender - who is comfortable playing on either side of a back four or as a wing-back - has excelled, catching the eye of Benitez.
Cass is the embodiment of a modern day full-back, comfortable carrying the ball forward with his pace and energy making him a real attacking threat.
And he combines that with a steely defensive resolve which has seen him become highly-regarded among Newcastle staff.
A former England under-19 international, Watts signed a professional deal at St James's Park last summer and has become a pivotal part of Ben Dawson's under-23 side.
The 19-year-old is a commanding centre back and, while it is his defensive performances which have brought him to Benitez's attention, he has also impressed at the opposite end of teh field.
Twice has Watts netted a hat-trick for the Magpies' younger sides, while he is yet to miss a game this season.
He impressed during the run to the last sixteen of this season's Checkatrade Trophy and will now be looking to take the next step in his progression.