Fremantle booked itself into an elimination final against Geelong at the MCG next Saturday night, beating the Demons 14.17 (101) to 5.10 (40) at Patersons Stadium to secure seventh place on the ladder with a 14-8 record.
Earlier results left Fremantle needing to win by roughly less than two goals to finish eighth, which would have resulted in a derby elimination final against West Coast next weekend.
Lyon said pre-match that the margin was too fine for him to consider "managing" Saturday night's outcome, so Fremantle instead went all out and notched a win that sent its percentage soaring beyond North Melbourne's.
The win came at a cost with a hamstring injury to key defender Luke McPharlin, who was substituted out of the match early in the third quarter.
McPharlin, who was replaced by debutant Tom Sheridan, has been in All Australian form and his loss is a big blow, with Cats star Tom Hawkins looming next week.
When the final siren sounded on Saturday night, Hawkins and Matthew Pavlich were tied in the Coleman Medal with 62 goals apiece after the Fremantle captain kicked two goals against Demon defender James Frawley.
Richmond's Jack Riewoldt (59 goals) can win the medal with a bag of four goals against Port Adelaide on Sunday.
As preparation for a finals campaign went, Fremantle ticked a lot of boxes on Saturday night, building its lead at every break. The team has now won eight of its past nine matches.
"The rehearsals over and the real season starts," Lyon said on Saturday night. "It's exciting for us. We've worked really hard.
"We come in in good form and we're fit and available. The MCG under lights against a triple premiership team, it's a really exciting challenge for us.
"We'll see where our effort and our systems take us."
Fremantle was dominant in the midfield, with David Mundy (31 possessions and nine clearances) and Nat Fyfe (30 and four) continuing their strong run of form.
Star ruckman Aaron Sandilands played alongside Jon Griffin for the third time this season and Lyon was pleased with the tall structure.
Sandilands was brilliant, particularly in the first half as Fremantle built a 32-point lead, holding Melbourne to just 2.5 at the main break.
The 211cm ruckman finished with 34 hit-outs and gave Fremantle a 41-27 edge in clearances, but he was also impressive when playing forward, kicking two goals.
Griffin, who came into the team this week as a replacement for Kepler Bradley, also kicked two goals. The team had eight goalkickers with Hayden Ballantyne (three) a livewire.
Melbourne coach Mark Neeld said Fremantle was a team with "strong and disciplined" players who would challenge Geelong next Saturday night.
"They were able to shut our ball movement down," Neeld said. "They're ability to go from offence to defence and vice versa is first class.
"It gives us a lot to work on. Some of the boys saw up close and personnel literally, especially defensively, how hard and how often you have to work to succeed in footy.
"I reckon it would have been good for some of our young players to see that tonight."
FREMANTLE 3.5 7.7 11.14 14.17 (101)
MELBOURNE 1.3 2.5 4.8 5.10 (40
GOALS
Fremantle: Ballantyne 3, Griifin 2, Mzungu 2, Pavilich 2, Sandilands 2, Walters, Mundy, Mayne
Melbourne: Fitzpatrick 2, Blease, Jones, Sellar
BEST
Fremantle: Mundy, Fyfe, Sandilands, Duffield, Ballantyne, Barlow, Mzungu
Melbourne: Grimes, Sylvia, Trengove, Fitzpatrick
INJURIES
Fremantle: McPharlin (hamstring)
Melbourne: Nil
SUBSTITUTES
Fremantle: Tom Sheridan replaced Luke McPharlin in the third quarter
Melbourne: Josh Tynon replaced Sam Blease in the third quarter
Reports: Nil
Umpires: Farmer, Dalgleish, Leppard
Official crowd: 32,687 at Patersons Stadium
