Winger David Williams bagged a first-half hat-trick as a switched on Manly overcame an early injury setback to back-rower Jamie Buhrer to score the first 20 points on their way to a 28-8 victory.
The Sea Eagles, who needed to win by 11 to clamber above the Storm on the NRL ladder, scored all six of their tries down Melbourne's left-hand side, in arguably their best performance of the season.
The margin might have been greater if captain and centre Jamie Lyon hadn't had a wayward night with the boot - missing five of his seven kicks at goal.
Manly, who had drawn with Melbourne earlier this season and lost twice to both the pacesetting Rabbitohs and Roosters, underlined their title credentials.
Starting Saturday's penultimate round NRL game two points behind the third-placed Storm, Manly produced a scorching start, piling on 12 points in the first 13 minutes.
Fullback Brett Stewart crossed twice before leaving the ground late in the game.
A besieged and uncharacteristically mistake-ridden Melbourne looked rattled in the first quarter.
The Sea Eagles performed with pace precision and confidence despite losing back-rower Buhrer after little more than 70 seconds.
He was taken to hospital for X-rays, appearing to suffer a rib injury after being caught in an awkward tackle between Ryan Hoffman and Ryan Hinchcliffe.
Within half a minute of Buhrer leaving the ground, Manly had their first try, with Williams crossing after Melbourne forward Jesse Bromwich lost the ball in the opening set.
The rampant Sea Eagles were in again in the ninth minute, when Stewart was set up by brother Glenn.
Williams crossed twice in the right hand side to expand his tally for the season to 17, after Manly players knocked back high crossfield kicks from five-eighth Kieran Foran.
Williams almost scored two more before the break and was outside Stewart when the fullback dived over for his second four-pointer.
Two minutes before the break, Melbourne finally got on the board when winger Sisa Waqa beat opposing winger Peta Hiku to a perfectly weighted kick from fullback Billy Slater.
In the second half, Waqa, on two occasions, and fellow winger O'Neill almost scored as the Storm played with more urgency and intensity.
Stewart scored Manly's fifth try before O'Neill crossed late for Melbourne.
Halfback Daly Cherry-Evans notched Manly's sixth try after Storm five-eighth Brett Finch fumbled a pass from an uncharacteristically out-of-sorts Cameron Smith.
MANLY 28 (D Williams 3 B Stewart 2 D Cherry-Evans tries J Lyon 2 goals) bt MELBOURNE 8 (J O'Neill S Waqa tries).
Referees: Jared Maxwell, Adam Devcich.
Crowd: 17,179 at Brookvale Oval.