"I totally understand the calls that we should be able to take an Australian team, because we should. We don't have any excuses," said Fuller.
Some may point to the Mystics' poor shooting accuracy on Monday night, on the back of an extremely quiet performance from captain Maria Tutaia, but the reality was the Auckland side were flat right across the court.
With the exception of midcourters Serena Guthrie and Laura Langman, the team lacked intensity on defence and were outdone by the Vixens' swift ball movement.
Fuller said for her side to have any chance in the coming playoffs, the team needed to front up in training this week and be open and honest about where they let themselves down.
"Things put us off our rhythm in the shooting end, we let up stuff in the defensive end and we were too distracted to actually rein it back in.
"Ultimately the onus is on myself as a coach. I'm responsible for this team, I'm responsible for the programmes we set and the trainings we plan so I'll be looking back at last week thinking, 'Where did we trip up? Were the trainings not intense enough? Were we too complacent going into this week because we were thinking we're there?'"
While it will be Australian sides standing between the Mystics and a maiden ANZ Championship title, Fuller's side can't afford to take their eye off their next assignment - the New Zealand conference final.
The Mystics will face the winner of Saturday's elimination final between the Waikato-Bay of Plenty Magic and the Southern Steel two days later in the conference final in Auckland. Although the conference final is not a knockout game, it will be regarded as a must-win, with the winner to host the second-ranked Australian side in the semifinal. The loser will have to travel to Australia to take on the competition's top team.
"The key thing is to keep being really positive about what we are doing and keep building on that. What we've got now is an opportunity to correct that and then prepare ourselves for the Australian teams in the semifinals."
What happens next
• Australian conference elimination final
NSW Swifts v West Coast Fever
9.18pm, Friday
Sydney Olympic Park Sports Centre, Sydney
• New Zealand conference elimination final
Waikato-Bay of Plenty Magic v Southern Steel
3.10pm, Saturday
Claudelands Arena, Hamilton
• Australian conference final
Queensland Firebirds v Swifts/Fever
2.18pm, Sunday
Brisbane Entertainment Centre, Brisbane
• New Zealand conference final
Northern Mystics v Magic/Steel
7.40pm, Monday
Trusts Stadium, Waitakere.