THE Black and Whites have turned giant-killers, knocking league tag powerhouse Leeton out of the Group 20 finals series with a gritty preliminary final win yesterday at Shark Park.

Griffith ran out 14-8 victors to earn the right to take on West Wyalong in the grand final on Sunday at the club's home ground, EW Moore Oval.

Perenial slow starters, the Black and White Panthers fired from the first whistle, grabbing a 4-0 lead through Mata Varasia which remained in tact for the remainder of the half.

But the Greens who have not missed a grand final since the Group 20 league tag competition was established threw everything at their inter-town rivals in a furious finish to the match.

Black and Whites skipper Shailyn Williams said her side was lucky to come away with the win.

"It was an incredible game and if there were another five minutes, it would have been even better," she said.

"Leeton's been champions for so long and it's been tight all year between us, them and West Wyalong but if you can beat the top side you deserve to be in the grand final.

"We've got a really good relationship and rivalry with Leeton and to not have to play them in the grand final is good."

Falesiu Moli and Mandy Meredith crossed for Griffith's two second-half tries but they wouldn't have mattered as much as they did if not for the side's collective defensive effort.

"Defence has been the key for us all season our attack was a bit sloppy but we pulled it together and did just enough," Williams said.

"Our support play was the reason we got over the line.

"It was a real team effort. Every single player stepped up, we had the perfect preparation and just took it as it came."

Having now met their pre-season goal of qualifying for the grand final, the Black and Whites will have their work cut out for them against West Wyalong but Williams said her girls are ready for the challenge.

"This is what we've wanted from the pre-season this was our goal, she said.

"Now we've achieved it we'll go from here.

"Whatever happens, happens."