A foot injury to forward Brandon Borrello has put a damper on Western Sydney's 1-0 defeat of a wasteful Sydney FC in the rivals' first derby of the A-League Men season.
Borrello's first-half replacement Zac Sapsford broke the deadlock against the run of play after 72 minutes on Saturday night, getting one over the side who once had him in on their books.
The win in front of 28,152 fans at Allianz Stadium exacts revenge on the Sky Blues for bundling them out of last season's finals series.
It also keeps the unbeaten Wanderers atop the ladder to finish the weekend.
"The great thing is we won in their backyard. It's really great for our fans, that's what I'm most proud about," said coach Marko Rudan.
Borrello pulled up sore in back-play just after the 10-minute mark, apparently hurt from a previous tackle.
He initially attempted to continue but fell to the ground shortly thereafter and was assessed for a left foot injury on the sidelines, in clear discomfort when the area was prodded.
He watched from the pine with ice on his foot and a pair of crutches at hand.
"It's just one of those things where your foot gets caught under a tackle," Borrello told Paramount Plus.
"It's all part and parcel of football. It could be a break, it could be nothing. There's definitely a bit of pain there, discomfort."
Any long-term absence would have implications for the Wanderers' ALM and Socceroos' Asia Cup campaigns.
Borrello was among Western Sydney's best players last season as they finished fourth on the ladder and has featured in seven of a possible eight games for the national side this year.
The injury came after Sydney targeted Borrello early, with skipper Luke Brattan collecting his right foot in a tackle and Jake Girdwood-Reich felling him in another.
The Wanderers' free kick from the Girdwood-Reich challenge was the closest they came to scoring in the first half.
Jorrit Hendrix curled the ball into the area, where Marcus Antonsson appeared to have headed home but VAR intervened to call Antonsson offside.
The Sky Blues had the better chances after the break, though.
Most notably, Wanderers goalkeeper Lawrence Thomas slipped over trying to pass to captain Marcelo and instead booted the ball straight to an unmarked Jaiden Kucharski.
But with all the goal before him and no Wanderers player within cooee, the Sydney young gun shot straight back to the keeper.
"In the second half I thought we were a lot better with the ball, we created opportunities, probably that last pass, that execution towards goal let us down," Sydney coach Ufuk Talay said.
The hosts were made to pay for that and their other missed opportunities when Antonsson bamboozled lone defender Girdwood-Reich and flicked on to Sapsford.
