Melbourne Victory went down to Moreland City 6-2 in the NPL2 West on Saturday.
Yazid Said twice brought Victory level at Campbell Reserve, but it was overrun in the second half.
Jacob Colosimo scored four times for Moreland, to go with a first-half penalty from Jesse Makarounas and a Christopher Cristaldo goal.
After an even start, Moreland took the lead through Makarounas' spot-kick, awarded for a foul by Victory captain Benjamin Carrigan.
However, Victory drew level in the 37th minute, when Said intercepted a back-pass and finished.
Moreland restored its lead immediately, though, when Colosimo headed in a right-wing cross from Cristaldo.
Said brought Victory level again six minutes into the second half, producing a neat finish after Jack Morton's pass deflected into his path.
But Moreland took control from then, Cristaldo finishing in a one-on-one before another Colosimo header.
Colosimo picked out the bottom corner from inside the area to complete his hat-trick in the 70th minute before adding his fourth to wrap up the host's win.
Head coach Gareth Naven's post-match thoughts
"I thought 33 minutes of our football was good football against Moreland City. I thought two minutes of not understanding how to defend inside the penalty box gets them 1-0 ahead, similar to a week ago, two weeks ago. The common theme is that we can get dominate in how we play, but in transition we cough things up and people punish us out of our mistakes. Just finding teams are not producing football against us, it's just that we're producing football for them which cost us four goals today – four mistakes. We want to be a team renowned for an attacking style of play, our reliability and survival independently of the ball, of space, of opponents, has got to be far better than what it is. That's the simple fact. At the moment, it's not and that's why we got beat 6-2."
NPL2 West 2019 Round 23
Moreland City 6 (Jesse Makarounas 33' pen, Jacob Colosimo 38'/67'/70'/84', Christopher Cristaldo 57')
Melbourne Victory 2 (Yazid Said 37'/51')
Melbourne Victory: Matthew Sutton (gk); Andrew Visciglio, Matthew Bozinovski, Benjamin Carrigan (c), Aaron Anderson (Aydin Mustedanagic); Anthony Lesiotis, Jay Barnett (Jack Morton); Brandon Lauton, Birkan Kirdar, Yazid Said; Nuh Sehavdic (Jack Palazzolo).
Victory's under-20s overcame Moreland City 2-1.