MELBOURNE has extended its undefeated start to the season with a 34-point win over Greater Western Sydney at Manuka Oval, where the hosts' woes were compounded by injuries to Stephen Coniglio, Phil Davis and Matt de Boer.

The effort, intensity and competitiveness of the Giants could not be questioned, especially compared to their preceding woeful loss to Fremantle in Perth.

But Leon Cameron's side, already under pressure and sorely missing injured stars Lachie Whitfield and Jesse Hogan, risks hitting crisis point soon if it fails to upset Collingwood in a must-win MCG match on Saturday night.

The Giants, desperate to make a statement after their first 0-2 start to a season since 2013, started strongly then dug deep after captain Coniglio and key defender Davis limped off in the second quarter and played no further part in the match.

De Boer, who curbed the influence of Clayton Oliver throughout the opening half, tweaked his hamstring in the third quarter to ensure yet another member of the expansion club's leadership group failed to finish the game.

The Demons, who conceded three of the game's opening four goals, seized control and withstood a spirited final-quarter challenge to triumph 15.12 (102) to 11.2 (68).

The result means Melbourne joins the Western Bulldogs and Sydney as the only teams yet to lose after three rounds, while the under-siege Giants and last-placed North Melbourne are the only sides yet to sing their song.

It is the Demons' first 3-0 start to a season since 2005.

Toby Greene's fourth and fifth goals, coming in the first two minutes of the final term, reduced the visitors' buffer to a six points, however, Melbourne settled with five consecutive goals, including two from speedster Kysaiah Pickett.

Pickett kicked four goals for the match to continue his eye-catching start to the year, including a remarkable third-quarter effort in which he created a turnover out of nothing then plucked the ball off the ground and snapped truly.

Captain Max Gawn booted two goals, bossed the stoppages and clutched five contested marks to headline the visitors' list of best-on-ground contenders, which also included Pickett, Jack Viney, Christian Petracca, Angus Brayshaw, Ed Langdon and Jayden Hunt.

GWS was forced to activate its medical substitute, thrusting Nick Shipley into the fray, after Davis suffered an innocuous lower-leg injury at the start of the second quarter.

Coniglio, who stood up alongside Tim Taranto and Josh Kelly after the Giants' midfield copped a week of heavy criticism, was in obvious discomfort after being tackled by Tom Sparrow.

Young Giant Brent Daniels also hurt his ankle late in the opening half, but was able to return to the park.

GREATER WESTERN SYDNEY   5.1    7.1     8.1    11.2 (68)
MELBOURNE                             2.3    6.5   10.7   15.12 (102)

Greater Western Sydney: Greene 5, Kelly 2, Himmelberg, Hopper, O'Halloran, Green
Melbourne: Pickett 4, Fritsch 3, Gawn 2, Jackson, Neal-Bullen, Petracca, Spargo, Brayshaw, Jordan

Greater Western Sydney: Taranto, Greene, Kelly, Ash, Haynes, Hopper
Melbourne: Gawn, Viney, Hunt, Brayshaw, Pickett, Langdon

Greater Western Sydney: Davis (ankle), Coniglio (ankle), de Boer (hamstring)
Melbourne: TBC

Greater Western Sydney: Shipley (replaced Davis)
Melbourne: Melksham (unused)

Crowd: TBC at Manuka Oval