Socceroo James Troisi played the roles of villain and hero as his Western Sydney Wanderers side fought back to force a 1-1 draw with local rivals Sydney FC at Stadium Australia.
In a free-flowing game which produced a cornucopia of chances, Sydney were the better side in the first half while the Wanderers finished the stronger.
Troisi was involved in both goals, which came within the space of five minutes just after the hour.
Referee Alex King deemed Troisi baulked Sydney's Milos Ninkovic on 63 minutes, with Kosta Barbarouses stepping up to convert the spot kick.
Wanderers levelled five minutes later when Troisi tapped home from close range, after Sydney goalkeeper Andrew Redmayne fumbled under pressure from Tate Russell.
The result extended the Wanderers' unbeaten A-league run against Sydney to five matches, their longest streak in the history of the fixture.
Wanderers' coach Carl Robinson described the penalty decision as "very harsh" and a "mistake", while his Sydney counterpart Steve Corica insisted it was the right call and suggested Troisi's leveller could have been rubbed out for offside.
For his part, Troisi told Fox Sports there was little he could have done to avoid a collision with Ninkovic for the penalty.
"I stood my ground and he went straight into me, so it's the wrong decision," Troisi said.
The Sky Blues hit the woodwork through Trent Buhagiar and played some delightful one-touch football in the first half, with Ninkovic and Anthony Caceres prominent.
Wanderers' goalkeeper Daniel Margush denied Sydney strikers Barbarouses and Buhagiar with fine close-range saves inside the first four minutes.
While Sydney made most of the play in the first half, the Wanderers also created a number of opportunities.
Tass Mourdoukoutas had a close-range attempt from a corner cleared off the line by Paulo Retre, and Redmayne saved from Russell and Keanu Baccus.
After the exchange of goals, it was the visitors who created more chances.
Given Sydney were playing just their second competitive game in six weeks, Corica was not surprised his players faded in the final quarter.
"I knew this was going to happen," he said.
"We just want to play regularly so we can get our match fitness going and get on a roll.
"You just want momentum and just each week playing games, and I know that will come very soon and we will be playing every three days and probably complain that we are playing too regular."
Robinson conceded Sydney were probably the better team in the first half, but rated his side as exceptional after the break.
"We were making silly, elementary mistakes when we didn't need to, we corrected that at half time," Robinson said.
"Full credit to the boys, they took that on board and we played through them a lot better and a lot cleaner in the second half.
"If there was another 10 minutes I fancied us to nick the winner."