In his seventh Origin appearance, Ponga was named man-of-the-match after a virtuoso display in which he scored a try, made three line breaks and gained 262 attacking metres as the Maroons clinched the title with a 22-12 triumph at Suncorp Stadium.

The Newcastle skipper could scarcely have done more to dispel suggestions that the five-season contract he signed earlier this year - reportedly worth more than $5 million - might not have been an astute investment.

"I never had any doubt that KP is definitely worth it," O'Brien told the Newcastle Herald. "He's still a young man, at 24.

"His best football is still in front of him. He's still learning the game. I'm confident he'll only get better."

Asked if Ponga could play at the same remarkable level on a weekly basis, O'Brien replied: "I believe so, I do.

"If he gets a really, really good pre-season in, injury-free, and banks some really solid training, there's absolutely no reason why he can't replicate that, week in, week out.

"As I said, his best football is still in front of him.

"I definitely think he can replicate that each week."

Ponga's heroics have put him in the frame for selection in Australia's 24-player squad at the end-of-season World Cup.

NSW and incumbent Kangaroos skipper James Tedesco would appear at short odds to be the Test fullback, but Ponga's ability to play five-eighth and possibly wing or lock could be an asset during what will be a six-game tour, providing Australia make it to the final.

"I think he's definitely got to be on that trip," O'Brien said.

"I think he's been good in all three Origin games, and he's been playing well for us.

"I can't see why they wouldn't want to have him over there."

Queensland coach Billy Slater said Ponga "had a great series".

"I've always had a lot of belief in Kalyn," Slater said. "I love working with him.

"He's a great guy and he wants to learn. He wants to be as good as he possibly can."

Ponga said in a post-game interview that he was "super proud" of the performance.

"Proud of the boys, coaching staff, support staff, proud of myself, to be honest, as well," he said. "This is my first series win, so it's a pretty surreal feeling."

O'Brien said he had heard from all three of Newcastle's Origin contingent - Ponga, Queensland centre Dane Gagai and NSW forward Jacob Saifiti - and was confident they would be fit to back up against Manly at Brookvale on Saturday.

Saifiti had a blinder in his interstate debut, scoring a bulldozing try and crunching out 135 metres in 37 minutes off the bench.

O'Brien said he was "easily" the best of NSW's forwards.

"I think it'll be great for his confidence," he said. "I thought he was outstanding.

"I think we'll certainly get something out of this when he comes back to the Knights.

"I was really disappointed about how negative some media were about his selection.

"We understand what he brings, in terms of impact.

"He's the sparkplug ... he found his front the whole night, scored a try, and that's exactly the reason he got our best-and-fairest award last year, playing predominantly off the bench."

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