The Saints took complete control in a dominant eight-goal third quarter, powering away to a 16.12 (108) to 9.15 (69) victory at Marvel Stadium on Saturday night.
High-profile recruits De Koning and Silvagni were jeered by Blues fans throughout their first encounter since the pair accepted big-money offers to leave in the off-season.
But De Koning stood tall and took strong marks to set up his two goals, while Silvagni did well in defence to help St Kilda (4-4) square their win-loss record for the first time this season.
"We were clear on the actions that we wanted them to deliver and they're really clear on their roles, and I thought they did that," Saints coach Ross Lyon said.
The victory came at a cost when Dan Butler sustained a hamstring injury, just hours after injury-plagued spearhead Max King was taken out of a VFL match with "hamstring awareness".
Nasiah Wanganeen-Milera starred with 31 disposals, five clearances and one goal, with co-captains Jack Sinclair (29 touches) and Callum Wilkie (22) also important contributors.
De Koning's ruck-forward partner Rowan Marshall (three goals) also shone, and the pair helped their midfielders get on top at the contest when it mattered most.
Mitch Owens (three), Liam Henry (three) and Cooper Sharman (two) also kicked multiple majors.
The Saints booted 8.4 to 1.4 in the third term - their highest-scoring quarter of the season - on the way to their fourth triple-figure tally this year.
"We took the game off them with our run and our ball movement and scoring off turnover, so that was really pleasing," Lyon said.
It was a familiar story for Carlton (1-7), who led by 18 points in the second term but again fell away dramatically after halftime.
The Blues laid just six tackles in a woeful third quarter, and conceded 12 of the last 14 goals on their way to a sixth consecutive defeat.
"Our ability and intent at the moment is not where it needs to be," Carlton coach Michael Voss said.
"We put ourselves in position to win the game, so that message seems to be working pretty well, but our ability to be able to do it for a longer period of time is not at the level it needs to be at.
"When the game is against you, you need to defend and you need to fight - and we are not doing it well enough."
Oliver Florent (30 disposals), Nic Newman (28) and Sam Walsh (24) won plenty of the ball for Carlton, while Brodie Kemp stood up in attack with three goals.
But they had few clear winners, with captain Patrick Cripps held to just 14 disposals and one goal under attention from Saints stopper Marcus Windhager.
Young defender Harry Dean sustained a groin injury and will be sent for scans to determine the extent of the damage.
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