Saints boss Stephen Robinson insists their disappointing opening day defeat will serve as a wake up call for his new-look side.
But the St Mirren gaffer believes his team will get better with time as they continue to get to grips with each other and their new system.
The Buddies were sluggish throughout their opening Group E tie against Arbroath in their first competitive game of the 2022/23 season.
They now face an uphill battle to top the group, relying on the Smokies slipping up against lower league opposition and the Paisley club winning every remaining match.
Robinson told Renfrewshire Live Sport: "We looked really leggy throughout the game. If we'd drawn and maybe won on penalties it might have papered over the cracks.
"We need to be fitter. As a team, we're much, much better than that.
"It's a wake up call. We need to do much better. We didn't press very well and we sat too deep.
"There's lots to work on. We had chances to score, hit the crossbar and had balls cleared off the line.
"Collectively, as a group we all need to do better. It's three weeks into a pre-season where we've added six players.
"Credit to Arbroath. They're a part-time team, they fought and scrapped to the death. There's a lot to be admired about them."
Saints boss Robinson handed five summer recruits their competitive debuts, with Trevor Carson, Declan Gallagher, Mark O'Hara, Toyosi Olusanya and Jonah Ayunga all in the starting line-up.
Arbroath handed a first start to ex-Livi midfielder Keaghan Jacobs, while Kieran Shanks led the line after joining from Inverurie Loco Works.
With Dick Campbell away on holiday in Turkey celebrating his wife's birthday, twin brother Ian was in the dugout leading the visitors.
St Mirren new boy Ayunga did well early on to hold up play and pick out Marcus Fraser on the right wing. His pinpoint cross found Alex Greive, who directed a header just wide of Derek Gaston's left post.
Fellow new boy Olusanya also went close to breaking the deadlock, slicing wide from a tight angle.
The Buddies dominated the opening half an hour but found the visitors tough to break down, with full backs Scott Tanser and Fraser putting in crosses that were comfortably dealt with.
Arbroath were the highest scoring side in the Championship last season but it took them more than half an hour to register their first effort on goal, David Gold blazing over from the edge of the bar after good work on the wing by Bobby Linn.
Ethan Erhahon played a superb through ball to send Tanser racing down the left wing. With three Saints players waiting at the back post, the full back couldn't beat the first man as the rusty, sluggish feel to the first half continued.
Kiltie set up Ayunga after a neat turn and pass, with the striker's powerful shot blocked away to safety.
The Buddies were extremely fortunate to go into the break still level after Arbroath produced the best chance of the first half just before Kevin Clancy called time.
Shanks did superbly to hold up the ball from a long ball before teeing up Scott Stewart on the edge of the box, who cracked a fierce low drive off the left hand post with Carson well beaten.
St Mirren returned from the break with a fire lit under them. Jay Henderson, who replaced Olusanya at half-time, popped a cross in with the ball eventually dropping to Greive in the box. The New Zealand international blazed over the bar when he should have opened the scoring.
Greive, and the vast majority of the crowd inside the SMISA Stadium, was screaming for a penalty moments later when Thomas O'Brien upended him as he moved into the box.
Referee Kevin Clancy waved away the protests, much to the disgust of Robinson and the home support.
St Mirren were much brighter in the second half and Henderson was unlucky to see his lobbed finish just clear the bar as the hosts began to turn the screw.
Moments later a superb Tanser free-kick picked out skipper Joe Shaughnessy, who crashed a header off the bar from just three yards out with keeper Gaston a spectator.
The Buddies had Arbroath penned into their own half, with striker Shanks coming to the rescue to clear Gallagher's powerful header off the line.
Robinson threw on young striker Kieran Offord for Greive as the hosts desperately sought a late winner.
The academy talent almost made an immediate impact. He did brilliantly on the left wing to dance past three Arbroath players before setting up O'Hara perfectly. The former Motherwell midfielder slammed wide with the goal at his mercy.
With the game looking to be heading for penalties Arbroath hit the Buddies hard.
Michael McKenna was given far too much time and space on the edge of the box and he picked out Dylan Paterson, who had come on just minutes before, to slam home the winner and send the 200 travelling Smokies home happy.
Still plenty of work to do for the Saints as they gear up for their Premiership opener against Motherwell later this month.
