In their first regular-season game together, both Sharpe and halves partner Jack Cogger produced big moments in the Knights' scrappy 10-8 win over Wests Tigers.
A young playmaker before he was switched to the backs in his mid-teens, Sharpe has the chance to make the Knights' No.6 jersey his this year.
But the opportunity comes with an intense spotlight on Newcastle's halves, after O'Brien used six separate pairings last season.
The club is also engaged in a high-profile pursuit of Parramatta playmaker Dylan Brown.
Newcastle completed at 53 per cent in the first half of Friday's win, blowing several opportunities before the break.
But the majority of wasteful errors came through errors by their backs, rather than at the fault of Sharpe or Cogger.
Sharpe scored one try out of dummy-half, while Cogger made a break out of his own end in the lead up to the other.
"It's natural it will take a few games," Sharpe said.
"But I feel like tonight we created a lot of opportunities and the last pass cost us a few times.
"Running together as a spine is something we still have to work on when we can team up and run shapes and through the middle.
After impressing while filling in for Kalyn Ponga at fullback last year, Sharpe was told before Christmas he could play No.6 this year.
He will form part of a dangerous left edge, with Ponga at his best down the side linking with centre Bradman Best and winger Greg Marzhew.
A natural runner of the ball, Sharpe said his biggest learning curve would be how to strike a balance with taking the game on himself and giving Ponga the best possible ball.
"He obviously gives you a lot of confidence there, you have to know your role, but then if Kalyn wants the ball he tells you he wants the ball," Sharpe said.
"You back him, he makes the right play more often than not.
"That's one thing we're working on. Me, him and Coggs linking up to get the ball one after another when those half breaks come.
"That is something I probably have to work, knowing where the game is at and when to take it on."
O'Brien praised Sharpe after Friday's win, backing the 20-year-old's smarts and willingness not to shy away in big moments.
But the coach will not commit to a halves pairing for the season, indicating selection was still results-based after last year's changes.
"I know a lot's been said about it and obviously I need to get some consistency there," O'Brien said.
"But there will become a point in time if we're not performing, I make a call.
"So it's up to guys that get the jersey to perform in the jersey. But right now, they'll be the halves next week."
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