Melbourne trailed by 49 points at one stage after an appalling second quarter, but actually won three of the four terms.
Yet they lost 16.11 (107) to 13.9 (87) to the Bulldogs, who have now won four of their final six matches for the year but were thoroughly unconvincing in victory.
Roos, who is understood to be the Demons coach-in-waiting, will be spellbound by Jeremy Howe's extraordinary final quarter mark in defence and how Melbourne proceeded to fight and excite as they fought back in the second half.
Jack Watts' four goals was also impressive - should the former No.1 draft pick stay - and co-captain Jack Grimes tried his best.
But he'll earn every bit of his reported $2 million annual salary if Roos has to lift the Demons north on the ladder with more efforts like that in the second quarter, in which Melbourne were towelled up nine goals to two.
The only semblance of fight the Demons showed came in a melee after the halftime siren sounded.
Most players from both teams were involved in the spot-fires, which spilled over the sideline and within touching distance of the crowd - Bulldogs ruckman Will Minson and Demons midfielder Jordie McKenzie among the most prominent.
Yet none of that energy was apparent in the previous 20 minutes from the Demons, who actually led by two points early in the second term before the Dogs poured on seven unanswered goals to take a 43-point advantage to halftime.
Forward Tory Dickson booted three goals for the Dogs, while midfielders Tom Liberatore and Matthew Boyd and Minson were excellent.
Boyd had 40 possessions for the match.
The Dogs round off their year having won eight matches for the season.
WESTERN BULLDOGS 4.3 13.6 14.8 16.11 (107)
MELBOURNE 4.5 6.5 9.7 13.9 (87)
Goals: Western Bulldogs - Dickson 3; Cooney, Giansiracusa, Hunter 2; Cross, Grant, Jones, Wallis, Campbell, Liberatore, Minson. Melbourne - Watts 4; Kent 2; Garland, Howe, Sellar, Viney, Dunn, M Jones, N Jones.
Best: Western Bulldogs - Liberatore, Minson, Boyd, Cross, Murphy, Dickson, Picken. Melbourne - N Jones, Watts, Grimes, Viney, Terlich.
Umpires: Jason Armstrong, Brendan Hosking, Leigh Fisher.
Official Crowd: 22,176 at Etihad Stadium.