Both Sharpe and Cogger had big individual moments in the Knights' season-opening win over Wests Tigers on Friday, as a scrappy Newcastle came from behind to win 10-8.
The Knights pair were always going to enter 2025 with a spotlight on them, with the club making a highly-publicised play for Parramatta playmaker Dylan Brown.
O'Brien made eight separate changes to his halves last season, using six different combinations as the club finished strong to make the finals.
And the Knights coach said he was not afraid to follow a similar approach this season, if unconvinced the right combination had been found.
"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, if we're not performing, I make a call.
"My number-one job is to try and get as many wins for Newcastle. For our club, for our town, for our sponsors.
"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."
Newcastle had taken Cogger and Phoenix Crossland into last year's finals as their halves, with Tyson Gamble coming off the bench.
Crossland has since started this season at No.9, while Gamble is recovering from a back injury and is hoping to be moving better by the end of next week.
Newcastle's attack struggled at times on Friday night, completing at 53 per cent for the first half.
But that was largely in part to errors made by backs, rather than in the halves.
After trailing 8-0 at halftime, Sharpe scored the Knights' first when he charged over from dummy-half.
Cogger then made a key break from inside his own end in the lead up to Newcastle's decisive try in the 10-8 win.
Friday marked the pair's first regular-season game together, with 20-year-old Sharpe moving to the halves in the pre-season after impressing in the backs last season.
"Fletch is a competitor," O'Brien said.
"I've said a heap of times. He's a footy nut, he's been playing it since he was four years old.
"He sees the game, he's intelligent, and he's only going to get better. He's two games in in the halves.
"He put himself in some situations that were really beneficial for the team. He doesn't run away from the challenge."
22°C