In a rain-reduced semi-final in Perth the power-hitting Marsh smashed 68 from just 40 balls to lead his Scorchers to victory over Shane Warne's Melbourne Stars and a grand final play-off against Brisbane Heat at the WACA on Saturday night.
Recently retired popular Test star Mike Hussey chimed in with a little late cameo 21 from 12 balls and veteran Adam Voges finished unbeaten on 36 from 21 balls with three big sixes.
Perth won from the last ball of the match in a freakish game in Australia's second season of Big Bash Twenty20 cricket.
Marsh, 29, single-handedly changed the course of the spine-tingling clash when he belted 27 with three sixes and two fours in the sixth over and first from first-game seamer Alex Keath.
Marsh, who is mounting a stunning case for recall to Australia's limited-overs team, collected his third man-of-the-match award for the summer.
Melbourne dropped a catch, missed a run-out and then committed a cardinal sin with a no-ball from what would have been the last delivery of the game and a win by three runs.
Perth needed 10 runs to win from the last over and Hussey smacked the last ball for four.
Melbourne made 2-183 from 18 overs after rain reduced the first innings and Perth's run-chase was calculated to 139 from 13 overs with a lengthy break between ahead of the home side's batting stint.
Ironically, Warne was not used at the bowling crease as Perth maintained a required run-rate of around 11 an over.
Surprise package Stars opener Cameron White smashed 88 in his finest domestic Twenty20 score in four years.
White slammed five big sixes and nine fours as a shock choice opener for only the second time in his career.
Veteran Brad Hodge was unbeaten on 70 from only 43 balls and the Scorchers chase reduced to 13 overs.
Perth was set a run-rate of 10.8 to win the match and play in the grand final as well as progress to the rich Champions League in October.
Shocks and a fiery confrontation highlighted an emotion-charged Big Bash semi-final with Warne, Hussey and Hodge in the firing lines.
In a startling move Warne relinquished his Melbourne Stars captain's duties to all-rounder James Faulkner and Hussey was confirmed as Perth's wicketkeeper.
Hodge then confronted umpires and complained vehemently at a nasty bouncer from the first ball he faced from firebrand Perth speedster Nathan Coulter-Nile bowling around the wicket.
The Stars top-order had belted 11 sixes when play was initially halted and prospects of the controversial Duckworth-Lewis assessment for any second innings run-chase.
Hodge had faced 30 balls for his half-century, including two fours and four sixes.
The Scorchers were being hammered bowling with a soggy and slippery ball.
Warne as well as his official vice-captain White faced suspension for Stars slow over rates through the tournament.
Under Big Bash regulations if a captain is found guilty of multiple slow bowling rates they can miss a match leaving Warne and his deputy in jeopardy of missing the grand final if they toppled Perth.
The surprises kept flowing when White opened the Stars batting after a lean tournament with blade.
White smashed five boundaries inside the opening four overs as the Stars made a bold start.
The great Warne was only back into the Stars outfit after serving a one-match ban for grabbing the jumper of controversial West Indies batsman Marlon Samuels at the MCG on January 6.
Perth captain Simon Katich won the toss and elected to bowl first up with some rain threatening and prospects of an interrupted innings with a Duckworth-Lewis interpretation to decide a final run-rate result.
The Scorchers confirmed newly retired international batting great Hussey would play and with wicketkeeping duties after the home side dropped regular gloveman Tom Triffit.
Winner of this second semi-final earns rights to host the Big Bash grand final at their home ground on Saturday night against an in-form Brisbane.
Perth surged into the semi-final finishing in second spot after dropping their opening two engagements of the eight-match home-and-away qualifying series, including a pasting from the Stars when skittled for just 69 at the WACA back on December 12.