Brisbane has all but confirmed its NRLW finals berth after Chelsea Lenarduzzi's last-minute try sealed a thrilling 20-16 defeat of ladder-leading Cronulla.

The Broncos' win came before Newcastle ended Gold Coast's top-four hopes and reasserted its own heavyweight status with a 46-10 thrashing of the Titans.

Made to defend their line for long periods in Robina, the Broncos rolled up-field on a seven-tackle set and took an unlikely lead when fullback Hayley Maddick found prop Lenarduzzi with a short ball.

The Queensland State of Origin representative barrelled over Sharks lock Brooke Anderson en route to the line to seal Brisbane's sixth-straight win with 16 seconds to spare in Saturday afternoon's match.

It would take a big loss to ninth-placed St George Illawarra next week and Parramatta to score similarly decisive wins in their last two matches for Brisbane to miss the top four.

It marks quite the turnaround for Scott Prince's side, who went winless across the opening two weeks of the season.

Winger Stacey Waaka left the field just before half-time in the only blight on the Broncos' afternoon, a leg injury looking set to keep the New Zealand rugby sevens Olympic gold medallist out for the remainder of her debut NRLW season.

Earlier, the Sharks scored twice in the six minutes after half-time to erase the Broncos' four-point lead, seeking to bounce back from last week's 40-0 humbling from the Sydney Roosters.

But winger Julia Robinson grabbed a cut-out pass from Maddick to bring the Broncos back within two points, before Lenarduzzi stepped up in the dying seconds.

In Saturday's later match, Titans five-eighth Sienna Lofipo dropped the kick-off and triggered a first-half onslaught from the visitors.

Newcastle's 34-0 lead at the break was the equal-largest in NRLW premiership history.

NSW second-rower Yasmin Clydsdale got past Lofipo for the first of her two tries on the fourth tackle of the day, before superstar fullback Tamika Upton began pulling the strings.

Upton chased down Georgia Roche's kick for her own four-pointer and an 18-0 lead after 16 minutes, before throwing the last pass in two more four-pointers in the first half.

The floodgates reopened when Ngatokotoru Arakua went to the sin-bin for the hip-drop tackle that sidelined Nita Maynard with an ankle injury in the second term.

While the Knights had the personnel advantage, Upton helped right winger Sheridan Gallagher become the first Knights player to record an NRLW hat-trick.

The win usurps last season's 38-4 thrashing of Parramatta as the Knights' most comprehensive in four seasons.

AAP