Saints striker Jonah Ayunga ensured his new facet weren't the victims of a cup upset after producing a medical first half brace at Central Park.
The summer time signing bagged his first purpose for the membership early on towards Cowdenbeath, turning cleverly previous two defenders earlier than firing into the underside nook to interrupt the impasse.
And he doubled St Mirren's lead shortly after when he tapped house from Joe Shaughnessy's flick on from a nook.
Whereas the Buddies struggled to interrupt down their cussed opponents within the second half, they nonetheless returned to Paisley with a welcome first aggressive win of the season tucked neatly below their belts.
Stephen Robinson handed a primary aggressive begin to younger goalkeeper Peter Urminsky, who began between the sticks instead of the injured Trevor Carson.
Summer season signing Ryan Pressure made his aggressive debut for the Buddies, slotting in at proper again with fan favorite Ryan Flynn reinstated within the coronary heart of midfield.
St Mirren began the sport on prime, urgent the Lowland League facet and incomes three early corners which all got here to nothing.
Centre again Charles Dunne cut up the defence with a wonderful go after breaking apart a uncommon Cowdenbeath foray ahead. He picked out Alex Greive on the left wing, who could not fairly pick a teammate within the field with the hazard finally cleared.
Saints keeper Urminsky was a spectator within the early phases of the primary half however the 23-year-old needed to be alert to disclaim Scott Sinclair's highly effective free-kick.
The striker's low effort was goal-bound earlier than Urminsky's good cease on the backside proper hand nook.
Simply earlier than the 20 minute mark the guests made their dominance rely. Younger ahead Kieran Offord did beautifully to maintain the ball in play earlier than establishing Ayunga within the field.
The striker's intelligent flip beat two defenders earlier than he powered house his first aggressive purpose for the membership with a fierce low strike that nestled within the backside nook.
The mud had hardly settled earlier than the summer time recruit grabbed his brace. A floated nook kick was knocked on by Joe Shaughnessy to the again submit, with Ayunga gratefully tapping house his second from shut vary.
The primary half petered out within the Fife sunshine, with Cowdenbeath resolute on the again and St Mirren already beginning to take their foot off the fuel.
Flynn flashed a cross into the field after a intelligent activate the left wing simply earlier than the break, with Cowdenbeath's defence simply scrambling the ball clear to remain in touching distance of the Buddies.
The guests returned from the break unchanged, seeking to press house their benefit and provides the travelling assist one thing extra to shout about than simply their lovely new black away package.
It was Cowdenbeath who threatened first within the second interval although, with Charles Dunne coming to the rescue to dam substitute Chris Aikamhenze's shot after he burst previous Shaughnessy into the field.
Robinson took the chance to combine issues up on the hour mark.
Greg Kiltie, Toyosi Olusanya and Richard Tait changed Flynn, Offord and Scott Tanser because the Buddies regarded to spark some life right into a forgettable second half.
Saints had one other let off when Shaughnessy's tried clearance from a cross failed to attach.
Fortunately for the skipper the Cowdenbeath striker wasn't positioned effectively sufficient to make him pay for his mistake.
The Saints virtually made it three when a very good quaint stramash within the field noticed the ball pop to striker Greive's ft.
The New Zealand worldwide's snapshot clipped the highest of the bar with keeper Mason McCready effectively crushed.
St Mirren made additional adjustments within the closing phases, with kids Jay Henderson and Celtic goal Dylan Reid each launched late on.
Tait tried his luck from distance with a fizzing strike that had a involved McCready at full stretch, however the ball sailed narrowly large of the submit.
In fact it was a forgettable second half efficiency from each side, solely brightened up when Cowdenbeath virtually nabbed one again with an extended vary effort that had Urminsky scrambling.
Fortunately for him it dropped simply over the bar, permitting the imposing keeper to stroll away with a clear sheet from his first begin for the membership.