With captain Marcelo facing a lengthy ban, Tomislav Mrcela has been tasked with leading Western Sydney's defence and ensuring the Wanderers regain their ruthless edge.
The Wanderers travel to face Macarthur on Saturday in fourth spot on the A-League Men table.
Victory would all but guarantee their return to finals for the first time in six seasons in an endorsement for the rebuild overseen by manager Marko Rudan.
The Wanderers have conceded the fewest goals (21 in 22 games) and kept a league-high nine clean sheets this season.
But there have been times where they have taken their foot off the gas, such as in last week's loss to Adelaide where all three goals were conceded from corners, that has stung their push to finish top of the table.
"If we had got those points we would probably be fighting for the premiers' plate," Mrcela told AAP.
"But you can't go back too much and you have to look at the future.
"There's always some games where you didn't deserve to win but you end up winning.
"I guess that's another step for us to progress and be ruthless in every single game."
Mrcela, who was Rudan's first signing last year, will be leant upon over the coming weeks.
His defensive partner Marcelo is awaiting the outcome of a Football Australia disciplinary panel after being charged with "assault" following the loss to Adelaide.
The Brazilian defender was involved in a fracas after placing Adelaide wonderkid Nestory Irankunda in a headlock, with Tom Beadling his most likely replacement.
"He's obviously disappointed about how he reacted," Mrcela said.
"We're pretty sure he's going to get a few games but hopefully it's not going to be that bad and we can get some wins without him and then welcome him back."
That starts with Saturday's trip to Macarthur whose finals hopes hang by a thread.
Even if the Wanderers have already thumped them twice this season and their opponents will be without Ulises Davila and Daniel Arzani, Mrcela believes Macarthur pose a considerable threat.
"People will say we beat them 4-0 twice, but they have some good players in that team," he said.
"For them it's a live-or-die situation to get into the top six.
"If I was part of a team that got smashed twice I'd be motivated to go and prove something."
