Ferreyra had seemingly drawn first blood in the ninth minute at a rain-soaked Campbelltown Sports Stadium on Saturday night, but a lengthy VAR review found the Wanderers defender to be offside.
Coach Ufuk Talay couldn't contain his anger on the sidelines, with the decision denying the visitors back-to-back wins following last week's 5-2 triumph over defending champions Auckland FC.
"From where I am, I can say it was not offside," he said.
"The hardest thing is VAR is there to fix errors, and offside is black and white.
"I would definitely have loved it to go in and be counted, but the reality is it didn't. I'm disappointed. We dropped two points."
Last season's wooden spooners, the second-placed Wanderers (1-2-0), at least remain undefeated to continue their revival under Talay.
Macarthur, who are led by new coach Sasa Ognenovski, are also undefeated after one win and two draws, and sit third, below Western Sydney on goal difference.
The visitors dominated the first half, with Wanderers young gun Miguel Di Pizio setting the tone by forcing a save out of goalkeeper Alexander Robinson in the opening minute.
Di Pizio had been involved in Western Sydney's disallowed goal, his curling shot from outside the box hitting the far post and spilling to a well-positioned Ferreyra.
The Wanderers still had the better of chances and would have surely drawn first blood before halftime if not for a quick-thinking Robinson, who matched it with proven match-winners Di Pizio, Nicolas Milanovic and Brandon Borrello.
The Bulls flipped the script in the second half thanks to the much-needed introduction of former Western Sydney winger Ryan Fraser in the 60th minute, alongside midfielder Musa Toure.
"I'd love to start him (Fraser) and love to have him on the field for 90 minutes," Ognenovski said.
"You see what he can do in a short space of time and we've just got to get his body right.
"The season's long and arduous, and yeah, there's another 23 rounds to go.
"He came in about three-and-a-half weeks before the season started ... he came in good nick, but not match fitness."
The Wanderers' momentum was stifled further when Milanovic was forced out of the game in the 71st minute with cramps, replaced by Hiroshi Ibusuki.
And after three minutes of added time, but in a wet-weather scrap, neither side could conjure the match-winner.
The Red and Black Bloc (RBB), the club's active supporter group, notably staged a 20-minute silent protest against policing for the clash.
The group claimed to have been directed by NSW Police to surrender their drums, megaphone and banners two hours prior to kick-off.
Fans also held banners that read "Stand Up For Fans. Not Police Demands" as a message to the Australian Professional Leagues.
After attendances nosedived during last season's wooden spoon campaign, the Wanderers enjoyed a large contingent of travelling fans in Campbelltown off the back of a five-star performance against Auckland.
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