Mapapalangi, 19, who did not look out of place in Newcastle's 28-22 loss to Brisbane, was picked at left centre again this week for the side's clash with the Titans at Cbus Super Stadium.

The Sydney product was named to play again despite Tuala, an 83-game centre/winger, being available for selection after being dropped to NSW Cup last week for missing the team bus the week prior.

"I think he didn't deserve to miss out, based on what he did last week," O'Brien said of Mapapalangi.

"We'll pick the team that is doing the job, and I felt Krystian did that.

"That says nothing about Enari. Enari has done the job for us for a long time, but at the end of the day I thought Krystian did his job.

"If you're doing your job, you get to keep it."

Mapapalangi was safe and solid on debut, making nine runs for 84 metres, five tackle-breaks and earning a try-assist for throwing a pass to his outside man Edrick Lee to score the first try.

Crucially, he made no errors and missed no tackles, making 10. He showed little, if any, signs of nerves.

"Considering the challenges the team faced of losing two rep players in Daniel and Tyson so late, it can sometimes dint your confidence, especially if you are a young bloke," O'Brien said.

"But no, I was really rapt for him. It wasn't a fluke, I think we've been really patient with Krystian.

"We've resisted the urge to hand him the jersey too early. He's earned that.

"In NSW Cup, particularly the last six to eight weeks, his defence had really improved."

The young centre will have his work cut out for him on the Gold Coast given he is likely to be on the side of the field Titans wrecking ball David Fifita will play.

The 107kg edge forward has been getting back to his best form in recent weeks, scoring a try and breaking eight tackles in each of the Titans' past two games.

"He is in a bit of a purple patch," O'Brien said.

"We did a really good job of handling David down here when we played them last.

"That's what you have to be with guys like him. Tino [Fa'asuamaleaui], certainly, you have to be committed to your contact on those guys."

O'Brien said he was "really confident" Daniel Saifiti would play despite the prop only coming out of COVID isolation today.

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He said Tyson Frizell, who was a late withdrawal with an ongoing rib problem last week, would likely play but would be given up until kick-off to decide if he does.

"Daniel is already testing clear and doing some training off-site, but more than confident," O'Brien said.

"Tyson, he's experienced, we'll give him right up to [the game] like on the weekend. We're better prepared having lived through it. He's earned the right to be given a say in whether he plays."

Saifiti is understood to be the first Knights player to contract COVID for the second time after almost every player had it in the off-season. Brodie Jones had it earlier in the season and played three days after emerging from isolation against Cronulla in round four.

The 24-year-old back-rower played 52 minutes but admitted he struggled to get through the game.

Both the Knights and Titans remained 1-17 on Friday. Their extended squads will be cut from 22 to 19 players on Saturday afternoon.

Newcastle have not beaten the Titans on the Gold Coast since 2015, losing the past six encounters. Equal last with Wests Tigers, the Titans are fighting to avoid the spoon.

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