With the score locked at 12-all deep into injury time, the Lions were awarded a penalty goal and Harding iced it, securing a 15-12 victory and rocketing the City boys into third on the ladder with two rounds of the regular season remaining.

The livewrire City outside back said he owed it to his side to kick the late dagger after missing a relatively simple shot at goal earlier in the contest at Dubbo's Victoria Park No.2.

"I've missed a lot of penalty kicks recently, I missed one from right in front just then, but I had to make it, the boys put in all their effort today and I couldn't let them down by missing it," Harding said.

"It's a big moment for us, 100 per cent, when (coach) Viv (Paasi) came here last year, we knew we were building towards something, whether we had the players or not, we were building towards something, this year I think we've got a team that can do it."

That sort of belief in the City camp makes for a huge derby next week at Pride Park, with Emus still undefeated on top of the ladder.

"The improvement's huge," Harding continued.

"But it comes down to all the work we've put in for it as well, this year we've got the mindset that we know we can make it, especially staying in the grind like that."

The visitor's first grade side demonstrated the depth of their improvements throughout the game's first half, applying pressure and pace and creating opportunities early.

One such effort produced first points of the game, sending Sia Nemani charging through the Roos' defensive line to score the game's first try after a bruising opening 15 minutes.

The conversion attempt by Harding went wide and it wasn't long before Roos drew level after an attack, led by Jake Styles, ended with first grade debutant Charlie Kempston pouncing on a grubber and grounding it out wide.

A successful conversion by Styles gifted the hosts a two-point buffer, but there was no sign of a momentum shift as both teams were forced into a gruelling back and forth battle late in the first half.

City's Steven Widders didn't waste his moment in the spotlight; plucking the ball out of the air and slipping past two defenders to shoot the Lions back in front with another try just before half-time.

Kempston grabbed his second in the final stanza to again draw Roos level with the Lions, and after that the fate of both sides rested on the right boot of Harding.

Kempston said the result was a bitter feeling for the Roos, but that it had given the side plenty to work on as they head into next week's bye.

"It was a pretty hard game," Kempston said afterwards, summing up his feelings on the effort put in by both sides.

"That was actually my first game in first grade, so I was pretty boogered to lose right at the buzzer after all that, but it's given us a couple of things to work on, we'll just look forward to next week and try and do our best to forget about it and keep moving forward."