The Rangers manager unexpectedly restored Allan McGregor to his starting line-up but the recalled goalkeeper was helpless to prevent St Mirren substitute Stephen McGinn – grandson of former Celtic chairman Jack McGinn – scoring the game's only goal with the home team's sole attempt on target.

Rangers' failure to re-establish a three-point lead at the top of the table over Celtic now leaves their rivals ahead on goal difference.

"We had a lot of possession in the early part of the game," observed Smith, "but our use of the ball was a little bit slow. Throughout the match, we never really created many clear cut chances. "It was possession for the sake of it, without any great penetration and we were never really incisive enough to get a goal.

"St Mirren set their stall out very well and worked hard to prevent us from doing that. We struggled in the final third and it was only really in the last 20 minutes that we applied some forceful pressure which looked as if it might get us a goal or two.

"In recent games away from home we have managed to score four goals at Celtic Park and three at Easter Road with the same team. People always pick faults with the team when you lose. It was frustrating that the winning goal was St Mirren's only attempt on target."

Smith admitted it was not easy to drop Neil Alexander, who had performed flawlessly in the three matches he played prior to yesterday, but feels McGregor has now regained the focus which made him Rangers' undisputed No1 last season. "It was a hard decision, because Neil has done nothing wrong in the games he has played," agreed Smith. "But I was maybe a bit unfair putting Allan straight back into the team at the start of the season when he wasn't as sharp as he was before he got injured.

"He has now had three weeks of intensive training, though, and has got that sharpness back. For the way he played last season before the injury, he deserves the opportunity to come back into the team now. It is hard on Neil but we are in a position where I feel we have two very good goalkeepers."

Kevin Thomson, carried off in the first half after a challenge from Garry Brady, was still in considerable pain when he left Love Street. "There is a lot of swelling on the ankle," said Smith.

Gus MacPherson, the St Mirren manager, was unaware it had been 22 years since his club last beat Rangers at Love Street but was unwilling to attach too much significance to the result. "You have to earn any three points you get at this level," said MacPherson, "and the effort and commitment in the first half gave us something to build on.

"We got the luck you need but if we had kept possession better in the final third, we could have caused Rangers even more problems. Every St Mirren player stood up and fought his corner, especially when Rangers bombarded us at the end. We are running out of games at Love Street now and we want to try and make each one of them memorable for the fans for the right reasons."

Goalscorer McGinn was assured of a warm welcome at the family home last night. The 19-year-old midfielder had previously scored twice against Celtic for St Mirren and was delighted to find the net against the other half of the Old Firm.

"My whole family will be delighted," smiled McGinn. "Some of them had been saying I was due a goal against Rangers. It's probably the best goal I've ever scored and the fact it was the winner made it more special than the ones against Celtic, because we didn't win either of those games."