In short:

The NRLW season got underway with the Knights defeating the Sharks 18-4 in a dominant performance.

Annessa Biddle and Georgia Roche were both sin-binned in a heated affair at Endeavour Field.

What's next?

The NRLW season continues on Saturday with the Titans and Roosters playing from 12.45pm (AEST).

Newcastle has started life without Jesse Southwell in victorious fashion, grinding past Cronulla 18-4 in a heated start to the NRLW season.

After their star playmaker departed to Brisbane in one of the biggest off-season moves, questions were raised on how the Knights would fare after making last year's preliminary final.

They shrugged off their doubters at Endeavour Field in Woolooware on Thursday, running in three tries to one to get their season up and running.

After an early try to Shanice Parker, Newcastle struggled to break down the Sharks's desperate defence in the second half, until an expert grubber from five-eighth Kirra Dibb led to a crucial try for Fane Finau in the 45th minute.

The Knights kept their foot on the throttle, and a penalty goal by Dibb followed by a first career try for interchange Simone Karpani sealed the win.

"[Coach Ben Jeffries] had a big emphasis on us playing some free-flowing footy, and not having a fear of that freedom," hooker Olivia Higgins said.

"I'm super proud of the girls, especially our halves. I think Georgia [Roche] and Kirra did a great job to allow us to play the style that we want."

The tense clash also delivered some fiery moments, with Sharks centre Annessa Biddle sin-binned for a hip-drop tackle on Newcastle fullback Lilly-Ann White in the eighth minute.

Moments later, the Knights spread right and found a diving Parker on the wing for the season's opening try.

Newcastle's Roche was also sent to the bin in the final seconds of the first half after making contact with the leg of her opposing number seven Chantay Kiria-Ratu.

Cronulla centre Rhiannon Byers then tore through the Knights defence early in the second period to level scores, before the visitors raced to victory.

The Sharks will be sweating on the fitness of interchange Stephanie Faulkner, who sustained an ankle injury when she emerged second best from a tackle in the first half.

Prop Caitlan Johnston-Green was also put on report for a crusher tackle on Knights captain Yasmin Meakes.

Cronulla are already without their captain and NSW representative Tiana Penitani Gray because of a knee injury, and the potential losses would make it difficult to replicate last season's preliminary-final finish

AAP