Melbourne Victory coach Kevin Muscat declared his team "lost composure" after Tim Cahill's wonder-strike that kick-started Melbourne City's 4-1 derby win.
Muscat admitted he wasn't looking forward to reviewing Victory's emphatic loss at Etihad Stadium, claiming it was "the worst possible night" for his team.
Victory were second to the ball for the majority of the match and City never looked back after Cahill opened the scoring in the 27th minute, lashing the ball into the top corner from 40 yards.
"The biggest disappointment for me, apart from the embarrassment of treating our fans to such a poor performance, is that we didn't really recover," Muscat said.
"If anything we went a little bit into our shell and lost composure and lost confidence, and then from that point on it became a very long night."
Muscat was frustrated by his team's inability to handle City's movement, with Neil Kilkenny stepping into midfield when the visitors had possession, plus Nicolas Colazo and Cahill pushed forward.
"We set up knowing that Neil Kilkenny would push into midfield and for 45 minutes we didn't come to grips with that, in terms of what we worked on and how we were going to nullify that," Victory's boss said.
"But from start to finish it was the worst possible night for us."
Muscat added that such a performance "can't happen again" but insisted it won't be difficult for Victory to improve ahead of next week's clash with Adelaide United and a FFA Cup semi-final versus City on October 25.
"[The derby display] was so far from what our normal standard that I'd suggested there's no reason to panic," he said.
"We'll get back to working on things but I suppose that's a big knock to the jaw tonight."