Dylan Macallister grabbed the winner as Melbourne Heart edged city rivals Melbourne Victory 2-1 in front of over 42,000 fans at Etihad Stadium.
David Williams put Heart in front in the 14th minute before Victory hit back ten minutes later with Marco Rojas finishing off one of the home team's many flowing moves, but the men in red and white took the three points thanks to Macallister's goal just before half-time.
While Victory dominated the first half with 58% possession, it was Heart who had the first real opportunity when Macallister shot wide in the eighth minute after goalkeeper Lawrence Thomas palmed the ball to the feet of the big striker.
Victory were keen to play the ball out from defence but manager Ange Postecoglou would not have been pleased with Adama Traore's mazy run, which led to the opening goal.
The left-back lost the ball in his defensive half and Heart attacked with Fred chipping to Matt Thompson, who nodded down to Richard Garcia and his cross was thumped home by Williams.
Most of Victory's attacks came down the left-wing in the first half and it was no different for their 24th-minute equaliser.
Marcos Flores received the ball from Traore and then released Archie Thompson with a no-look pass, before the Socceroo crossed to Rojas to score his first goal for Victory.
Victory could have scored twice following their equaliser with Guilherme Finkler curling a shot just wide and then the Brazilian found Flores in a packed penalty area but the Argentinian's shot hit the bar.
Just two minutes later, Heart made Victory pay.
Mate Dugandzic burst onto Michael Marrone's flick, went past Mark Milligan and crossed from the right-hand side, placing the ball perfectly between Adrian Leijer and Thomas and allowing Macallister to side-foot the ball into the net.
The home team came out firing in the second half but it was Heart who had the best early goal-scoring opportunity when Dugandzic beat the Victory offside trap only to be denied by Thomas, who blocked the attacker's chip with his chest after charging out of the area.
Postecoglou's team pressed forward throughout the half but Heart should have finished the game on the counter-attack on numerous occasions.
Heart's best chance came in the 75th minute when Williams picked up Leijer's poor back pass but could not beat Thomas, who had a great game in goal for Victory.
The home fans left the stadium ruing a late miss as Thompson shot over the bar from close range in the 90th minute.