Trailing 1-0 for almost an hour, Celtic eventually hit their stride to claim a 4-1 victory and stretch their unbeaten run in domestic football under Rodgers to 34 matches.
The Celtic manager was full of praise for St Mirren afterwards, rating them above Aberdeen, Rangers or any of the other Premiership rivals he has encountered in his first season in Scottish football.
“St Mirren would hold their own in the Premiership,” said Rodgers, pictured, whose team currently hold a 27-point lead in the top flight.
“They are the best team we have played domestically, without any shadow of a doubt. They have good organisation and Jack Ross has obviously gone in there and made an impact.
“We played Alloa at Celtic Park when he was manager, so I had an idea of his coaching ability. He had them well organised and there are moments in games that make you think about the level of coaching. Certain things happened that make you think, ‘Oh, okay’. It’s little details that can define coaches.
“They have good speed, they have young players with enthusiasm and energy. They play football and St Mirren have been our biggest threat domestically this season, for sure.
“How they are at the bottom of the Championship, I do not know.” Rodgers admitted to a degree of concern when, with 52 minutes on the clock, Celtic were fortunate to avoid going 2-0 down when Moussa Dembele sliced an attempted clearance of a free-kick against his own crossbar. St Mirren had opened the scoring from a well-worked set piece, finished by Harry Davis.
“Listen, you’re not here on holiday,” said Rodgers. “From those two set pieces, we had an issue. Moussa had a swing at it and it hit the bar. It fell for us and we were then able to go and take control of the game.”
Goals from Mikael Lustig, Scott Sinclair, Dembele and substitute Leigh Griffiths saw Celtic finally assert their authority on the tie, leaving Saints boss Ross with mixed feelings afterwards.
“The first emotion for us is disappointment because we did come here to win and progress to the semi-finals,” said Ross.
“People might think that was foolhardy, but that was our ambition. We were halfway towards doing that, so there is that disappointment that we haven’t managed to achieve what we wanted to.
“But when you put that aside, there is pride in how we performed and in how well we made Celtic have to play to win the game.
“You just don’t know how things would have panned out if the one that hit the bar had gone in for us. I still think we would have had to withstand a lot of pressure, because Celtic had introduced Leigh Griffiths by that stage and changed the dynamic of the game.
“To win here you need to play very well and you need good fortune. That moment was possibly that little extra bit of fortune we needed today but didn’t come our way. If it had gone in, we possibly could have progressed. But it didn’t and thereafter it was difficult for us.
“What Brendan has said about us is a good compliment for the players.
“I’ve spoken about it since the window closed. I believe we have a stronger squad now with a better balance.
“They should take enormous satisfaction from it but, equally, they need to have a desire to prove it game in, game out.”