While the Dogs have made the last two finals of the National Hockey League, the team lost several key personnel this season and entered the campaign with lower expectations than in the past few seasons.
But the Dogs surprised everyone, including themselves, with an upset 2-1 win over Auckland in the opening match.
They could have easily beat the defending champion by more had they made the most of some of their many opportunities in the final two quarters.
The teams will meet today in one semifinal.
Canterbury plays Midlands in the other.
On paper, Auckland will start as the favourite.
But Ashton said his side had taken an enormous amount of confidence from the way it has been playing without last year's stars.
''This year we've lost Hugo Inglis, Blair Tarrant and Eddie Ockenden,'' the 29-year-old said.
''Eddie would be in the top five players in the world and the other two are not that far off, as well.
"To lose those three guys left quite a big hole, so it is a pretty good effort for us to make the top four.
"I think it shows how much depth we've got in the region.''
Southern's fortunes reversed dramatically when the league introduced a region of origin rule in 2011. Before that, the best players tended to head north and not return to the fold.
Southern struggled without its top players but during the past few years has developed some superb structures which has allowed the team to maintain a high standard.
And that had been the most satisfying part of the season, Ashton said.
''To get to the semifinals this year is probably our best effort so far. We are not relying on anyone because we can't ... we don't have our superstars.
"It is a classic example of a star team as opposed to a team of stars. Hopefully, that will carry us through [today].''
Auckland has beaten the Dogs in the previous two finals but both matches went to overtime and one was decided by a shoot-out.
Ashton believes it will be another keenly contested fixture. Southern will look to build patiently through its structures which have served it so well, while Auckland will rely more on individual brilliance and flair.
''I know they are worried as well. They hate playing us because we always do really well against them.
''They like a really free-flowing game because they have quite a few stars in there with those silky sort of skills.
"But we've been pretty good at stopping them playing in that style and stamping our own authority on the game.''
In the women's tournament, Auckland will play defending champion Midlands, and Canterbury and Northland will play the later semifinal.
Southern will play Capital in a crossover game today. The best it can finish is fifth, if it wins its two remaining games.
NHL
The semifinals
Southern Dogs: Chris Ashton, Callum Bailey, James Bishop, Jason Dungey, Nick Elder, Hamish McGregor, Jeremy Morris, Joe O'Connor, Nick Ross, Kane Russell, Craig Smith, Andrew Matthews, Kirk Shimmins, Alistair Birchall, Kim Kingstone, Joe Crooks, Campbell Paton.
Auckland: Ryan Archibald, Jonathan Bilkey, Marcus Child, Dean Couzins, Robbie Creffier, Jamie Dwyer, Ketan Hari, Jignesh Keshoor, Tom Loudon, Tom Lysaght, Devon Manchester, Sam Miskimmin, Arun Panchia, Jared Panchia, Daniel Panchia, Ben Radonovich, Michael Ritchie, Dwayne Rowsell.
Men's semifinals
Auckland v Southern Dogs, 2pm
Canterbury v Midlands, 4pm
Women's semifinals
Auckland v Midlands, 10amCanterbury v Northland, noon.
All games at North Harbour Hockey Stadium
