A first half beauty from Callum Booth and second half goals from Murray Davidson and Stevie May secured Saints' safe passage through to the Scottish Cup 5th Round.
The game was in doubt at half-time due to floodlight failure but after a 20 minute extension to the interval play resumed and Tommy Wright's men picked up from where they left off in 2019 to make it 6 consecutive matches unbeaten.
It was a glorious afternoon at McDiarmid Park as Saints faced Championship outfit Greenock Morton for a place in the Scottish Cup 5th Round.
Both sides paid tribute to Bobby Brown with an impeccably observed minute's silence, after the former Saints manager sadly passed away during the week.
Current Manager Tommy Wright started with a 4-4-2 formation with Chris Kane and Stevie May leading the line for the home side.
However, it wasn't one of the Saints strikers who would send the home fans into raptures early on.
Left-back Callum Booth saw the ball break to him at the edge of the area and side-footed the ball into the top corner with his weaker right foot to give Saints a dream start to 2020.
The home side continued to cause problems down the right-hand-side in the early stages through Drey Wright and Anthony Ralston but the visitors more than held their own and responded well to the early setback.
On 9 minutes, Morton came dangerously close to an equaliser when Luca Colville found himself free in the area but somehow blazed his effort over the crossbar to the relief of Zander Clark and his defence.
Five minutes later and it was Morton 'keeper Danny Rogers who was called into action when Murray Davidson's reflected cross almost crept under his crossbar.
Saints forced a series of corners without creating a clear cut opportunity while Morton continued to push for an equaliser.
Colville fired a great cross without any takers in yellow, before Tumillty came close after chasing in a rebound from a Zander Clark save but the Morton number two fired wide.
The visitors were knocking on the door before half-time when the players were forced into an extended break.
Floodlight issues saw the interval last 35 minutes before finally play could resume. And it was Morton who appeared to get out the blocks quicker after the delay without creating much in the way of chances.
After ten minutes of pressure Saints finally got a foot hold in the game again and David Wotherspoon tried his luck with a volley on 55 minutes which was well blocked on the six-yard-line.
However, two minutes later Tommy Wright's men would double their advantage.
A Drey Wright corner met the head of Murray Davidson who glanced his effort into the top corner leaving Danny Rogers with no chance.
Morton tried to find a way back into the game bringing on John Sutton up front and then former Saints midfielder and Scottish Cup-winner Chris Millar in midfield.
But two minutes after Midgey's introduction things got worse for the visitors when Stevie May made it 3-0.
Playing in his first Scottish Cup match for the Club since the 2014 Final, May broke away from the Morton defenders before showing great compsure to knock the ball past Rogers and into the back of the net.
With the game pretty much put to bed, the Manager used all three subs to give players game time with Wallace Duffy replacing Ralston, Scott Tanser coming on for Wotherspoon, and Stevie May making way for Callum Hendry.
The visitors were unable to get a consolation goal and Saints comfortably saw out the match to book their place in the 5th Round draw tomorrow evening.
SAINTS: Zander Clark, Anthony Ralston (Wallace Duffy 77), Callum Booth, Liam Gordon, Jason Kerr (c), Drey Wright, David Wotherspoon (Scott Tanser 81), Ali McCann, Murray Davidson, Chris Kane, Stevie May (Callum Hendry 81)
UNUSED SUBS: Elliott Parish, Michael O'Halloran, Jason Holt, Liam Craig
SCORERS: Booth (3), Davidson (57), May (73)
MORTON: Danny Rogers, Reghan Tumillty, Stephen Welsh (John Sutton 65), Brian McClean, Kyle Jacobs, Jim McAllister (c), Robbie Muirhead (Reece Lyon 80), Lewis Strapp, Nicky Cadden, Luca Colville (Chris Millar 72), Jack Baird
UNUSED SUBS: Sam Ramsbottom, Peter Grant, Kalvin Orsi, Cameron Blues
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