Melbourne sunk to one of their lowest ever ebbs on Friday night against a rampant Penrith, conceding a half-century for the first since 2003 in the 50-10 shellacking.
It means the Storm will enter next Saturday night's match against the Warriors with a losing record this late in a season for the first time since 2018, after three straight losses.
There is an argument no side would have come close to Penrith on at CommBank Stadium, with Bellamy labelling them "head and shoulders" above the rest of the NRL.
But the veteran Storm coach still made no secret of his frustrations at Melbourne's defensive frailties, after Penrith bust their line 10 times.
"Some of our contact tonight was poor at best," Bellamy noted afterwards.
"That was the disappointing thing for me."
Melbourne will at least welcome centre Moses Leo back from concussion against the Warriors, while Jack Howarth (hip) will also be some chance.
The Storm are without several key players, with prop Tui Kamikamica's stroke last week leaving him the latest player on the sidelines.
But the Melbourne coach said he would have one obvious message for players.
"We just go a little bit harder," Bellamy said.
"If they don't want to go harder, well, they can go and play in reserve grade and we'll bring some young blokes up. That's how we always handle these situations.
"We've just got to learn from tonight and just be better, that's all. The disappointing thing for me was our defence.
"You don't have to be a brain surgeon to be a good defender. You just need to work hard and be determined."
The only good news for Melbourne on Friday night was medical stuff clearing Harry Grant of a knee injury, after it was jolted in contact.
But Grant also suggested he had little to smile about, with Melbourne losing the key moments.
Nowhere was that more evident than in the first half with Penrith leading 10-6, when a Melbourne attacking raid was ended with Siulagi Tuimalatu-Brown being pushed into touch.
By the next time Melbourne touched the ball they trailed 20-6 a few moments later, with Penrith needing little invitation to take the game away from rivals.
"That's not good enough," Grant said.
"We need to look in the mirror and look at us before we're looking at opposition teams."