Oan Djorkaeff scored his first St Mirren goal to spare Jim Goodwin's team another embarrassing Betfred Cup slip-up against Edinburgh City.
The son of French World Cup winner Youri struck tucked home a late penalty to seal a 1-0 win over James McDonaugh's League Two minnows.
And it keeps Saints' faint hopes of topping Group H alive as they bounced back from their opening defeat to Dunfermline.
Goodwin's Paisley homecoming on Sunday was wrecked by the Pars' 3-2 triumph – leaving the new boss to admit his squad was shy of five quality players.
No new faces had arrived by the time of the Citizens' visit to Paisley and again the top-flight side looked lost for ideas against lower league opposition.
Apart from an overly-ambitious Cody Cooke overhead kick attempt and an off-target Kyle Magennis header, the Buddies created little during a drab first period.
In fact, it should have been Edinburgh who went in ahead at the break after spurning the best chance of the opening half after 22 minutes.
Gary MacKenzie gifted possession to former Hibernian winger Alex Harris and the capital outfit shifted the ball quickly through midfield to release skipper Josh Walker through on goal.
But the former Aberdeen men went for a flimsy chip when he needed to put his foot through the ball to beat Vaclav Hladky, leaving the Czech stopper to casually pluck the ball out of the air.
Goodwin waited 20 minutes into the second half before sending for Danny Mullen as Saints continued to toil.
The striker soon had the ball in the net as he converted from fellow substitute Ethan Erhahon's cross but Saints' celebrations were quickly cut short by an offside flag.
But Goodwin was spared another frustrating result when ex-Hearts defender Craig Thomson fouled Paul McGinn in the box with two minutes to go, leaving Djorkaeff to fire home from the spot.
