Coach John Aloisi said a lack of camera angles at AAMI Park potentially cost Western United a decisive penalty before spectacular strikes from Hamza Sakhi and Terry Antonis consigned them to a 2-1 ALM defeat to Melbourne City.
Leading after Michael Ruhs' 13th minute opener, United appealed for handball against Scott Galloway three minutes into the second half following multiple Daniel Penha attempts on goal.
The incident, however, passed without referee Ben Abraham being called over to review it on the pitchside monitor.
"The beginning of the second half was a clear handball but [Abraham and fourth official Adam Bavcar] said there were not enough camera angles to see if it was a handball or not," Aloisi said.
"It's a definite handball because his arms are out. I don't know how many camera angles you need."
Sakhi equalised for City just three minutes later, lacing a 25-metre half-volley into the top corner after United failed to clear a corner.
Antonis then won the game in the 83rd minute when he rifled in a first time effort from the top of the box.
"I think anyone that was watching knows that we deserved more out of that game," said Aloisi.
"We were good, we were very good against a very good side."
United had logged a promising start when Angus Thurgate ghosted behind City's lines, swivelled to face goal and dropped a cross onto Ruhs at the back post.
Their compact midfield and well-organised defence, meanwhile, were making it difficult for City to fashion high-quality chances only a week after they'd romped to an 8-1 win over Brisbane.
"We were terrible in the first half but that was due to some great pressure, great work and great intensity from the opposition," said City coach Aurelio Vidmar.
"For the purist, probably wasn't the greatest of games. But we found a way to win and I think that's important."
Unbeaten in eight matches, City rise to fourth on the table but will now sweat on the fitness of Sakhi and Marin Jakolis after both limped off.
United, meanwhile, remain bottom of the league with two wins and nine losses.
"I don't understand how we've lost nine games, I really don't," said Aloisi.
"But, we have, so we have to deal with it and try and make sure that we rectify it."
