Adam Le Fondre marked his return from Mumbai City by scoring from the spot in the 76th minute, 13 minutes after entering the fray.

Ivan Vujica had blocked fellow substitute Alexander Baumjohann's ball into the area but the ball flicked up off the Western United man's thigh onto his outstretched arm.

After a VAR consultation, referee Shaun Evans reviewed the incident and awarded a penalty, with Le Fondre coolly converting.

"There wasn't much of a reaction from the Sydney FC bench or the players," Rudan said.

"Shaun Evans was five metres from it, saw it clearly, saw on the replay a few times, made a decision to play on, everybody was happy with it and then all of a sudden it gets called back.

"... Once again, we get dudded. We don't deserve it. I'm sick and tired of getting treated like a second-rate citizen in this league. It's just not fair.

"... For us to continue to be on the wrong side of these decisions - it's shattering for me, for my chairman, my CEO and everybody involved in this football club."

Post-match Le Fondre said he had disagreed with the awarding of the penalty, while coach Steve Corica said the current handball rule was too unclear.

"It's (the handball rule) ridiculous," Le Fondre told Fox Sports.

"Obviously I'll take it - because it's a bit of a weird law. But I didn't think it was a pen, personally, if that was my preference."

Saturday's game at Ballarat's Mars Stadium was United's fifth in 16 days and followed an away trip to Adelaide, then a stint on the road with games against Brisbane, Western Sydney and Perth.

"We've travelled across five different cities across the country in 14 days and played five games ... that is extremely unfair," Rudan said.

"(My players) should never have put on a performance like that today. (It was) superhuman - and I told them that after the game."

The spot-kick conversion proved the game's only goal, after Sydney had dominated from the outset without reward, and keeps the Sky Blues in the hunt for second place.

United goalkeeper Ryan Scott turned in a stellar performance, making 11 saves and denying Kosta Barbarouses and Trent Buhagiar on multiple occasions.

"We were obviously creating a lot especially in the first half," Corica said.

"It was good to have Adam coming on and scoring the penalty - a clean sheet was important as well at this stage of the season.

"... At some stage (Le Fondre's) going to start - whether it's midweek (against Melbourne Victory) or on the weekend against the Wanderers."

Australian Associated Press