Shane Mumford isn’t underestimating the power of a round-one win.

Beat St Kilda on Sunday and the star ruckman reckons Greater Western Sydney could become “quite scary” by the middle of the AFL season.

For the first time in their short existence, the Giants are favourites for the Etihad Stadium fixture against last year’s wooden spooners.

While coach Leon Cameron says it’s hard to judge a team by their opening game, Mumford sees it as a “massive” opportunity.

“With such a young group, confidence is a massive thing,” he told AAP.

“And if we can start the year off really well by getting a win first game, obviously the confidence just grows and builds.

“If that happens, we could be quite scary come the middle of the year.”

With the addition of experienced campaigners Joel Patfull and, in particular, Ryan Griffen, Mumford said the Giants were standing taller than he’d seen them since joining in 2014.

Both recruits will debut for the club in Sunday’s match after impressive hitouts in the pre-season competition.

Mumford labelled Griffen one of the competition’s “most elite midfielders” and expected him to play a huge role in the side’s mission to reach the finals.

“From what I’ve seen so far in the pre-season, with our match play and the games that he has played, he’s going to be massive for us,” he said.

“You need these guys talking and leading the young blokes.

“As we saw when Heath (Shaw) and I came along, it makes them stand a little bit taller.

“Obviously with another year of experience … I’d put us in a good chance of actually making the finals this year.”

The Saints, meanwhile, are coming off a difficult pre-season, which ended with a 106-point NAB Challenge thrashing by Hawthorn.

A number of injuries have forced coach Alan Richardson to bring in some fresh faces to his senior squad, including Ahmed Saad following his 18-month ban for a positive drug test.

Despite the inexperience, GWS coach Cameron reckons forward Josh Bruce and young midfielder Jack Billings are real dangermen – but not as great as Nick Riewoldt.

Cameron plans to pit new recruit Patfull and Phil Davis against the Saints skipper, who’s still grieving the death of his sister a month ago.