Despite a remarkable run of form that has seen Sydney revitalise what had shaped as a wretched season, the bye might have come at the perfect time as the Swans count the cost of a remarkable upset over the reigning premiers.

West Coast's miserable run at the SCG, not having won there since 1999, continued on Sunday as it looked thoroughly lacklustre in a 45-point defeat.

It comes after a month when the Swans pushed powerhouses Geelong and Collingwood, and defeated Essendon and North Melbourne in the weeks prior.

Making the win even more astounding was how limited the Swans were in the second half.

A hamstring injury to veteran Jarrad McVeigh stopped him after a polished first half while Colin O'Riordan and Jackson Thurlow copped head knocks that ruled them out of the clash.

The Swans are 4-8, so finals aren't really a consideration, but the way they were able to guts it out in classic Sydney fashion bodes well for John Longmire's side in years to come.

The coach was effusive in the aftermath.

"I can't think of a time that we've had that and still finish as strongly as what we did. It was one of the better wins I can remember, really," Longmire said.

Fair enough, too. Co-captain Josh Kennedy (knee), dasher Zak Jones (hamstring) and lockdown defender Nick Smith (hamstring) are among those sidelined.

"To do what we did today with five or six regular players out of the senior team to start with, including three or four real key midfielders, and to not have any rotations really except for one person on the bench for the second half, was just fantastic," Longmire said.

Winning is always easier when Lance Franklin fires - and fire he did, bagging 5.4 in a phenomenal display.

His preparation was hampered by groin surgery, while a hamstring complaint forced him out for a month, but the 32-year-old looked in brilliant touch on Sunday.

The reason why was simple.

"He's been able to train more," Longmire said. 

"He's missed four weeks of training off the back of no pre-season.

"There's no mystery to it. He's just getting going again. He's like every other player. He's been able to train more, he's been pushing himself to get out there more and he's feeling better about himself."

Being shorthanded and not having the ability to rotate off will make for sore bodies, as the coach quipped.

"Some blokes will struggle to walk to their car tonight," Longmire said.

One of those is the injury-stricken Daniel Menzel, who looked to be struggling in the final term after having his pre-season wiped out by a problematic groin.

He was initially left out of the team on Friday, before being recalled minutes later after a calf strain forced Will Hayward out.

Longmire said the reason was innocent.

"It was a lodgement of the paper mishap," Longmire said.

The Swans will be back at the SCG in a fortnight to face Hawthorn.