Inconsistency. Travel. And Sam Kerr.
Kerr, the Perth and national team striker, has lit up the competition this season and propelled the Glory to a home semi-final on Saturday against the Sky Blues.
In a topsy-turvy competition characterised by lop-sided scorelines and upsets, Stajcic can't pick winners in this weekend's semi-finals.
Premiers Canberra United host last season's champions Melbourne City on Sunday to decide the grand finalists, to be played on Sunday February 12.
But Stajcic said his former club side would be doing well to get past the Kerr-inspired Perth, which wasn't one of the likely contenders at the start of the season.
"She's carried them a long way. It's a team effort but she's been the stand-out. Its a real credit to her and the team," he said.
— Sydney FC (@SydneyFC) February 3, 2017
"I predicted Sydney, Canberra and Melbourne City would be at the top and Perth have had a great season.
"Sam has a good team around her but their success has certainly been down to a lot of her individual efforts."
Kerr has 10 goals this season, second only to Canberra's Ash Sykes in the golden boot race.
Stajcic said he thought Sydney FC had the strongest squad "on paper" but had struggled to produce their best.
"Going to Perth off the back of two losses, confidence won't be high. They haven't got real momentum going in," he said.
"Their last win was that 6-1 against Canberra (on January 3) so they've got it in them but inconsistency is hard to overcome when you come to a semi-final."
Stajcic sees the second semi-final, due to be played in 37-degree heat, as a battle between defence and attack.
"City are probably the best team in the back third and the middle third but they've lacked that cutting edge up front," he said.
"If Canberra pay their best they'll be hard to stop as they've got so many weapons in attack."
— Melbourne City Women (@MelbCityWFC) February 2, 2017
Alongside Sykes is Matildas captain Lisa De Vanna, who helped City to a championship last season but is now clad in United's green shirt.
De Vanna missed the first half of the season and Stajcic believes the 32-year-old is finding her feet in time for the finals.
"Last week was the first week when I saw her project herself into the game and create lots of chances and goals. She's got her rhythm back and if she can continue, I'd give Canberra the edge."