The hosts of Sunday's match at Flinders Field, the Stingrays of Shellharbour, are ruing missed opportunities in both their opening two games.

In round one, the Rays found themselves down 36-8 against Albion Park-Oak Flats before storming back to get within a try in the final minutes - before ultimately losing by 12.

Read more: St George Illawarra forward Josh Kerr concerned over NRL expansion talks

Then in round two, the Rays were just seconds away from winning the eighth Shellharbour Showdown against the Sharks, before a late Declan Morrissy try resigned them to a 22-all draw.

"In the first round, we got off to a really slow start and probably got in our owns heads a little that because we're a big side, we'll just be able to roll through teams easier than we did," Rays captain Kieran Rankmore said.

"We lacked a lot of energy against the Eagles, which really let us down and although we picked it up in the second half, it was all too little, too late.

"Then that Shellharbour loss was a really tough pill to swallow, as we had that game in the bag - we were all really deflated after the final whistle.

"In my eyes, we should have put 30 points on them but our discipline and poor ball-handling coming out of our own really let us down.

"Despite the two losses, we've taken plenty of positives from them, as we have a lot of new players we're trying to integrate into our squad - especially in the spine."

Read more: St George Illawarra unveil Matthew Head as new NRLW coach ahead of 2021 campaign

That leaves skipper Rankmore and his Stingrays, who've had the week off like all other Group Seven sides, desperate to chalk up their first win on Sunday.

"Over the past fortnight, we've emphasised how important this week's match is because you really need to get wins early otherwise you'll be playing catch-up towards the end of the season," the 31-year-old said.

"There's no reason, on any given day, we can't beat any team in this competition.

"We've got an extremely talented squad at the club and it all hinges on when it starts to click for us.

"When we finally breakthrough for that first win, it'll be a huge boost of confidence for the squad and everyone we believe what we can actually achieve as a group.

"I've been part of some talented teams over the past 10 or so years, including a couple of grand final sides, and I can't see why this team can't at least be playing semi-finals, let alone making it through to the big dance.

"Winning, just like losing, can become a habit and we need to get that going.

"Obviously the club has struggled in the past but the strength and depth across all grades are phenomenal at the moment, it's all about proving that on the field, starting from this weekend.

"One of our main strengths is obviously in the forwards, including the likes of Jake Kamire, Juvi Samiu and former Superoo Luke Shiels, and I know they have a handy pack too, so whoever wins that battle, will go a long way to getting the two points on Sunday."

But it won't be easy against an undefeated Jamberoo side, who easily accounted for Kiama and the Park through the opening two rounds.

"It's a solid start to the season but we aren't getting complacent because there's still a long way to go," Jamberoo captain/coach Jono Dallas said.

"Once you get through the first six or seven rounds, that's when it really starts to paint a picture of how well or poorly you're travelling as a team.

"We feel we're good enough to win every game we play in and we should through our hard work, mental toughness and commitment in the two opening rounds.

"No one plays their best footy at this early stage of the season, as everyone is still working themselves into the year but it's getting to a point now where that early-season excitement is wearing off and we really need to knuckle down."

Read more: Wollongong Roller Hawks out to make history in 20th anniversary year

As confident as they are, the 2017 premiers are well aware Sunday will be their most physical challenge of the season.

"The Stingrays are a very improved outfit with one of the biggest forward packs in the competition," Dallas said.

"It's going to be a big test physically but I'm confident our boys will be up to it.

"Their [Stingrays] size isn't just in the middle of the park either, with their outside backs also being very strong, so all 17 of us are going to have to come prepared to roll up our sleeves and dig deep for one another.

"This early in the season, most teams are concentrating on playing their own game and getting your own house in order first but you'd be silly not to mention their firepower - because otherwise, it could really hurt us."

A win on Sunday would move the Kevin Walsh Oval-based club to 3-0 but Dallas hosed down any talk September talk just yet.

"Starting 3-0 obviously lays a strong foundation for the early part of the season but we won't be getting too carried away if we do win - because we know there's another 15 round games to play," the halfback said.

"The main thing for us is being self-aware of how we're travelling as a group, not putting any pressure on ourselves and not playing outside of our means.

"If we do those and continue to improve each time we step on the field, we're a chance to play finals footy in 2021."

Read more: Patzold prepares for emotional 320th marathon in honour of mother

Elsewhere in round three, following a weekend off due to Anzac Day, Gerringong will host Nowra-Bomaderry on Saturday, in their first home fixture at Michael Cronin Oval in 2021.

Then on Sunday, the Knights play the Gorillas at the Kiama Showground and Albion Park entertains Shellharbour at Centenary Field - with Milton-Ulladulla having the bye.

All first grade matches kick-off at 3pm.