Man-of-the-match Marsh top-scored with 86 off 53 balls, belting five sixes and as many fours in another scintillating innings.
He was in single figures when his skied pull shot was dropped over the Marvel Stadium boundary by Jake Fraser-McGurk.
The powerful right-hander made the Renegades pay for missing the difficult chance, playing the lead role in the Scorchers' mammoth total of 5-206.
Only once - when Marsh hit an unbeaten 93 in a tally of 3-213 against Brisbane Heat in January last year - have the three-time BBL champions posted a bigger score.
Nic Maddinson (67 off 41) and Aaron Finch (68 off 43) combined for a brilliant 130-run partnership from 77 balls to put the Renegades within sight of what would've been the fourth-highest run-chase in BBL history.
At one stage they needed an achievable 77 off 41 balls, with nine wickets in hand.
But Marsh struck to dismiss Maddinson - caught behind by a diving Josh Inglis - putting a significant dent in the home side's charge.
Australia's T20 World Cup-winning captain Finch returned from a knee injury and was in fine touch until he skied a catch off Ashton Agar.
Agar (2-23, three overs) then trapped Mohammad Nabi lbw for a first-ball duck as the Renegades ran out of steam, losing 3-14 in the space of three overs before finishing at 5-185.
"When you've got 200 on the board you're only ever one wicket away," Marsh said.
"It's pretty rare that you get wickets in T20 cricket as a medium pacer but to break the partnership was a great feeling.
"There was a bit of luck with the wicket ... but it was a nice wicket to get.
"There's certainly no secret (with my batting). I'm just enjoying my cricket and being really consistent with everything I'm doing off the field."
The result improved the Scorchers' record to 5-0 for the season.
"The boys have started beautifully and this time last year we were 0-5, so it's a nice turnaround," Marsh said.
"We've got a lot of experience in this team and tonight we were tested, so it was great we all stood up when it mattered.
"Our bowling group was fantastic and hopefully we can keep winning."
Marsh's brutal display with the bat set the platform for Perth as Laurie Evans (42 not out) and Ashton Turner (20 off 11) played important cameos, pushing the score beyond 200.
Evans found the boundary six times in his 16-ball innings as the Scorchers took 67 runs off the final four overs, including 42 off the last two.
Renegades import Reece Topley (0-44, four overs) coughed up 24 runs from his final over - the 19th of the innings - which included two no-balls.
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