YOU ONLY need to speak to his teammates to realise that Phil Davis has an enormous influence at Greater Western Sydney and is one of the team's most important players.

Just like Josh Kelly's sublime skills and Toby Greene's X-factor, Davis' leadership in defence places him on the top shelf of stars at the Giants.

But the co-captain isn't just a stopper. He can play too, and his battle with Sydney superstar Lance Franklin could just about sway the result at Spotless Stadium on Saturday.

It might only be the impact of winning a single one-on-one contest between the pair, the match-up is that huge.

Injury-free over the past three seasons, Davis has been one of the competition's most reliable backmen, but the 27-year-old recognised he needed to bring more offence to his game in 2018, and he's elevated his impact significantly.

He's ranked equal second (with Adelaide's Rory Laird) for intercepts behind Richmond's Alex Rance this year and has averaged a career-high 15.2 possessions per game.

Injured teammate Heath Shaw told AFL.com.au that the skipper is the anchor of the Giants' team.

"I think over the years his leadership and playing form has grown together," he said.

"He's gone from being a lockdown defender like 'Presti' (former Collingwood defender Simon Prestigiacomo), to evolving with the game and bringing in more offence.

"This year he's taken it to a new level, backing himself to fly for marks and getting more involved in the attacking side of the game, and that comes on the back of confidence.

"The best defenders in the game beat their opponent, then work off them.

"We need six defenders when they have the ball, but once we get it, we want all six to become attackers and we need everyone to buy into that.

"Phil's dedicated in everything he does, and if he feels he needs to work on something, he'll go bull a gate at it until he gets it right."

Shaw said the way Davis has reshaped his game this season has been impressive.

"He's a strong personality and a strong leader, he's very opinionated and backs himself in, and as a captain of a developing football club you love to see that," he said.

"Being outside of Melbourne and in a non-footy state he doesn't get recognised as much, but his form speaks for itself at the end of the day.

"I have no doubt he's in contention for an All Australian spot, but to be honest I don't think he really cares too much.

"He's got one focus and he's pretty stubborn in working on where he wants to get too."

The Giants' backline has gone through some changes over the past 12 months, with the departure of Nathan Wilson to Fremantle, the long-term absence of Zac Williams with an Achilles injury, a change of position for Adam Tomlinson, and the return of Adam Kennedy and Matt Buntine from ACL surgeries.

But through all that, the GWS defence is ranked fourth for points against, and wingman-turned-running half-back Lachie Whitfield said the team has Davis to thank for.

"He's the brains of the team just as much on the field as he is off the field," he told AFL.com.au.

"His direction and poise have really galvanised our backline.

"In terms of structure and reminding everyone what needs to be done in the moment, he's really good.

"We know he's going to win his one on one contests and play his role, but he goes above and beyond to help other play their role as well.

"He's just a really good leader and a really good captain.

Whitfield has been a revelation since stepping in to cover the loss of Williams and he credited his captain for helping him adjust to life as a defender.

"He helps me a lot in terms of my positioning and my overall defence," he said.

"I probably didn't have a defensive bone in my body until this year, but he's guided me through it.

"His direction and talk really helps me a lot.

"I can get drawn to the ball sometimes and I ball watch, so when I drift off he always yells at me to come back."