Derek McInnes last night refused to blame Aberdeen goalkeeper Joe Lewis after his howler cost the Dons a spot in the Betfred Cup last eight.

The stopper made an inexplicable gaffe with just minutes left on the clock to provide St Mirren a route into the latter stages. The ball squirming through his legs despite Jamie McGrath's strike looking relatively tame.

Gutted McInnes absolved his goalie, though, instead telling of his frustrations that his players did not start the game on the front foot as he'd have liked. Energy levels looked questionable, too, but it was Dons' failure to come out the blocks firing that irked the boss.

"You need that bit of a break in a cup-tie but unfortunately for us it's a mistake that has put us out," he said. "But Joe has saved us more times than that, so we won't be blaming him tonight.

"It's been a tough week for us with three away games in six days at Ibrox, Hamilton and then today. But I would've thought any fatigue issues would have come up later in the game but we didn't start well, so I can't sit here and say that's a reason. We had key players missing but we still had a good enough team to start the game competitively.

"We'll be better than we were today, I'm just disappointed we didn't start with the aggression needed for a cup game."

Dylan Connolly's pace and trickery was on full view early doors for Jim Goodwin's men and it was his endeavour that brought about the opener. The Irishman danced his way towards the box and was bundled over by Jonny Hayes. Up stepped returning winger Ilkay Durmus who curled a brilliant free-kick into the corner of Joe Lewis's net, the goalkeeper didn't move.

Any expectations of a Dons walkover against the Premiership strugglers looked seriously misjudged and it could have got really difficult for the visitors early when Richard Tait struck the post with a long-range drive. That would not have sat well with McInnes who made his frustrations abundantly clear from the touchline.

There was barely time to draw breath in the first-half and Saints were demanding a penalty when Jon Obika went down inside the area under pressure from Tommie Hoban. It looked a clear spot-kick but referee Don Robertson waved it off. It almost didn't matter, though, when a brilliant piece of skill from Connolly again carved out another opportunity for the hosts. He spun Greg Leigh with a deft touch before lashing an effort straight at the keeper.

Obika was the next guilty party to spurn a chance, but this was a sitter. The striker found himself unmarked inside the six-yard box after a misunderstanding between Dons defenders. It looked easier to score - so much so there were club officials celebrating in the stands - but their cheers were premature when he inexplicably drilled his effort wide of the mark.

Then the inevitable, when Aberdeen finally strung together an attacking move and scored an undeserved equaliser. Niall McGinn took advantage of a lapse in Saints' concentration to shoot beyond Jak Alnwick, albeit the stopper got a significant touch before it trickled over the line.

Aberdeen's Hoban thought he had turned the game on its head minutes into the second-half but his header from a corner sailed wide from close range. It was, like Obika's in the first, a head-in-hands moment for the defender.

The action had been non-existent as the game wore on and it took the absolute blunder from Dons keeper Lewis to separate the two. Sub Junior Morias found Jamie McGrath outside the area. He struck a speculative effort towards goal which the keeper parried, but the ball somehow bounced beneath his grasp and into the net. An unexpected disaster from the usually composed and consistent captain.

Saints manager Jim Goodwin was pleased to see his side through to the next round after dominating the first-half, though he was miffed that they couldn't add more goals to their game.

"I have to say I was really disappointed to come in half-time 1-1," he said. "We dominated the 45 minutes and if we had been 3-0 up I don't think there could have been too many complaints.

"There has been a great belief among the group, there's been a lot said outwith the dressing room but we know why our poor run happened. Covid took its toll but we're on the other side of that now. Aberdeen will be looking for revenge next week so we'll have to be wary of that."