The New Zealand side were destroyed in front of their own fans at Westpac Stadium, powerless to stop John van 't Schip's marauding visitors.
Addressing the media after the match, Merrick sought to mark down the result as a one-off, and called on his squad to respond positively in the weeks ahead.
"You can't analyse a game like that," he said.
"Everything went wrong. You'd spend the whole time trying to fix everything."
When asked if he sensed something was amiss prior to kick-off, Merrick said: "Quite the opposite. You can never really predict performance from the warm-up or the atmosphere in the dressing room. Every time you think it's poor, they go out and win. And vice versa.
"The boys were well prepared, they were organised... the boys did their best for the fans that came, they worked very hard, but nothing went right today. All you do is write is it off. It's how it effects the next two or three games that's the most important thing.
"We've got a good enough team to bounce back and get three points in the next two or three games and that's what we've got to aim to do."
Quizzed on whether or not he could recall having overseen a similarly catastrophic result, Merrick made reference to Melbourne Victory's hammering away to the Newcastle Jets in January 2007, but was quick to make the distinction between the different circumstances surrounding the matches.
"A 4-0 loss once the weekend before finals," he said.
"And it was probably the best thing that ever happened then, because we never lost another game and went on to win a grand final. That was another team though. This team, it's important they show their resilience to bounce back. It's an important measure of their character."
And has Merrick ever been in charge for a heavier defeat in his coaching career?
"I can't think of one. I probably have, but I've obviously hidden it from my memory," he joked.
"Not a pleasing day at the office, but I feel for the boys. They gave everything."
Finally, the Phoenix coach revealed Spanish midfielder Albert Riera is set to see a surgeon in Auckland about his groin and abdominal injury, which is likely to see him join Louis Fenton on the sidelines for the rest of the season.
