Melbourne had little idea of the monster they were creating when they beat Penrith in the 2020 NRL grand final.

"I've never thought of it like that," Storm coach Craig Bellamy said at Thursday's grand final press conference.

"I just worried about what we're doing. Obviously winning that grand final was a great moment for us.

"But there were some things the Panthers have clearly grown from as well."

If Bellamy has not thought about the flow-on effects of the 2020 decider, Penrith certainly have.

The Panthers pored over hours and hours of footage of that year's decider, when they fell 26-0 behind early in the second half before mounting a late comeback.

Players were shown eagle-eye replays of at least five off-the-ball incidents during the match, where they believed Melbourne had roughed up their players.

They were told of how key players had been targeted, with a belief that Storm players had regularly pushed the envelope.

And the most brutal bit of feedback was the belief that Melbourne had walked over them, and that Penrith needed to stand up for themselves in the future.

"It's hard to say if it was the most important game (in our run), but it was definitely an important part of our journey," Panthers coach Ivan Cleary said.

"It definitely lit a fuse of fire in that we wanted to make sure we learned from that.

"We had a really good run but we were taught a lesson that day. Not just by the Storm, but just on big occasions."

The years since the 2020 decider have seen Penrith branded as "arrogant" and "mug lairs" by some critics, making enemies in the likes of Canberra and other NRL rivals.

In reality that was due to the Melbourne loss, with ex-Penrith prop Spencer Leniu conceding after that the Storm were ruthless and his players were not.

The response has been emphatic, with three straight premierships and now another shot at Melbourne on Sunday night at Accor Stadium.

"We were so young, we hadn't been a part of it (before)," Panthers co-captain Isaah Yeo said.

"They taught us a few lessons in that game, how to win on the big stage.

"I've felt we've been able to carry those lessons on and pass those on to new players that haven't experienced it. That was a big one for us."

But through it all, Cleary insists Penrith's desire to learn from the Storm is based on respect, still believing Melbourne are the benchmark.

"When we set our sights on becoming something, (that was it)," Cleary said.

"I am very attracted to consistent and professional sports teams.

"If you look across the world in different team sports, I think Melbourne would stand up against anyone."