Despite Ton fans' efforts to add colour to the occasion with a France-themed day in honour of out-of-contract midfielder Fouad Bachirou, the vibrant spectacle off the field was not matched on it.
In the 16th minute, impressive Hearts loanee Jamie Walker waltzed past several weak challenges and ended his slaloming run by slamming a firm finish past Alan Combe to open the scoring.
Another of Rovers' loan players, Dunfermline's Pat Clarke, sealed the win, and ensured Fred's appreciation party would never quite get into full swing, with a second-half brace.
For his first goal, strike-partner John Baird sent him clean through on goal with a visionary clipped pass in behind the Ton defence.
The high defensive line gave Clarke acres of space to run into, and he showed Peter Weatherson a clean pair of heels before calmly placing the ball past Combe.
He completed his double three minutes later, popping up totally unmarked at the far post to head home Jamie Walker's teasing cross from the right.
The only bright spot on a miserable day came with 13 minutes left on the clock when Lewis Hawke, son of former fan favourite Warren, nodded home a Michael Tidser cross to net his first senior goal for the club.
However, even that positive could not deflect from a desperately disappointing display which saw Ton drop to eighth in the table - one place worse off than the season before.
Morton manager Allan Moore said: "It's a disappointing end to a disappointing season, there's no hiding from that."
Morton (4-4-2): Combe; Evans, Weatherson, Graham, O'Ware (Di Giacomo, 63); Young, Bachirou, Smyth, Tidser (Frizzell, 87); MacDonald, Campbell (Hawke, 73).
Subs not used: Orr, McGinlay (gk).
Raith Rovers (4-4-2): McGurn; Thomson, Murray, Hill (Vaughan, 86), Dyer; J. Walker (Callachan, 65), A. Walker, Davidson, Hamill; Baird, Clarke (Casalinuovo, 70).
Subs not used: Williamson, Laidlaw(gk).
Referee: Kevin Clancy