The 22-year-old wingman rejected considerable interest from West Coast and the Western Bulldogs at the end of last season, signing a new three-year deal with the Dockers.
Now he's one win away from becoming a premiership player, with Fremantle taking on the Brisbane Lions in Saturday's decider.
"I definitely knew that we had a lot of talent on the list, and that it was possible and our coaching staff would give us every chance to get to the big stage," Erasmus said.
"The belief's definitely there. We're confident that we've got the fittest team in the competition.
"We've done a mountain of work and it's shown throughout the year."
Erasmus played 16 games last season, including three as the substitute, but was dropped multiple times.
This year, the Johannesburg-born ball-winner is one of only seven Dockers to have featured in every game.
"I stuck to what I was doing already. I work really hard on my game and probably just relax a little bit off the field," Erasmus said.
"I've found a better footy/life balance and it's allowed me to play footy with a bit more freedom.
"Our coaching staff have done a great job and made my role really clear and I worked really hard on that over the pre-season.
"I was fully confident if I did stay that if I kept working on my game the opportunity would come."
Erasmus lauded Fremantle's resilience throughout a rollercoaster finals series, which started with a surprise home loss to Hawthorn.
The Dockers made use of their double-chance, bouncing back to knock out Geelong and Sydney en route to the grand final.
"Being one of two WA teams, there's a lot of pressure over in the west for one of the teams to perform - or both to perform," Erasmus said.
"We can feel the weight of that sometimes and the resilience we've shown over the finals series ... is pretty good from a young group."
15°C