Sometimes, big games can come down to a single moment.

That may not have been strictly the case on Sunday evening as the Penrith Panthers took out their third straight premiership on the back of a dramatic comeback, but it certainly had plenty to do with it.

And the big moment on Sunday seemed to come out of the blue, and almost as a result of Brisbane building a head of steam too quickly for their own good.

After heading into halftime only miraculously down by two points following a Thomas Flegler try under the sticks on the stroke of the break, it was an Ezra Mam hat-trick that lit up the second half.

Realistically, at the break, it felt as if the Broncos were going to be up against it. They had spent most of the game to that point camped on their own line, making a lot more tackles and only just bettering 40 per cent of possession after 40 minutes.

That should have told through fatigue in the second half, but they came out of halftime firing, and cut the Panthers to ribbons through their left edge attack.

Reece Walsh and Ezra Mam were both able to capitalise off the excellent work of Payne Haas, Patrick Carrigan and Flegler to take the lead out to what should have been more than good enough to take home the chocolates and the Provan-Summons trophy.

2023 NRL Grand Final - Panthers v Broncos

With that 24-8 lead and off the back of a penalty, the Broncos went onto the attack, only to completely and utterly lose their head given the game situation.

Instead of taking the conservative option, they went to the ultra risky. There was a lot of time to go in the game and nothing wrong with continuing to play football, but it was time to take stock of the game.

A 16-point lead with 22 minutes to go is never going to be mowed down if you play the percentages, turn the ball over in the right areas and force a few repeat sets.

Instead, the Broncos played more like they were 16 points behind.

Walsh, who had been phenomenal during the period where the Broncos scored those points, passed a ball off the ground. It was an offload that was never on, and the ball hit the ground. While they retained possession, Payne Haas then decided to keep pushing the ball along with another offload, before a Herbie Farnworth pass hit the ground.

Stephen Crichton dove on it, Moses Leota ran for plenty of metres on the next play, and while Penrith didn't score in that set, they did a few later, and those nerves crept in for the Broncos.

It was all about changing the momentum of the contest for the Panthers, and they did just that on the back of that Brisbane error.

The bottom line, regardless of that one play, any further errors or any other events, is that the Broncos should never have lost from the position they managed to put themselves in.

It was as disastrous of a collapse as you could possibly imagine, and the images, comments and interviews post-game proved they really didn't have any understanding of what just happened.

Adam Reynolds was as good as speechless, while coach Kevin Walters struggled to find the words to sum things up during the post-game press conference, eventually landing on 'feeling empty' and 'pissed off' at the loss.

Despite what should have been a period of the game to sit back and take stock, Reynolds admitted post-game that the on-field instruction was to keep playing footy.

"The message was pretty clear out there. Keep playing some footy. We probably just went a bit one-out and they had all the momentum, and we just couldn't get it back, so it's disappointing," Reynolds said.

As mentioned, there is nothing wrong with that, but as a good game manager, he needed to take the reigns and calm his team down.

Instead, things got away from the young Broncos' outfit very softly and while that one play didn't win Penrith the game and their third straight premiership, it was the catalyst for the turnaround in events which transpired afterwards.

The play went to show one of the fears over the Broncos pre-game - that experience would simply get the better of them.

In the end, that's exactly what happened during that final 18-minute collapse.

Brisbane will be better for the run and back next year for another tilt at their first premiership since 2006, but this one is going to sting for a long, long time.