
St Mirren ended Celtic's 100% start to the Scottish league season by defeating them in their first league game of the season.
The only effort on target in the opening 45 minutes was Mark O'Hara's head, and it was the only goal of the game.
Celtic had not lost a league game in over a year, but they were beaten by the impressive hosts' second after the break to leave them two points behind Rangers at the top.
Third place on goal difference is now occupied by St. Mirren after a third league win of the season.
chant from the away end disrupted the applause in memory of Queen Elizabeth
The Celts were off target with speculative efforts in the first half.
When Ryan Strain advanced on the right, he delivered to the back post for O'Hara to score.
The visitors had not trailed in a previous game this season. They responded with a blocked Mooy shot and an overhead kick.
At the break, Reo Hatate and Jota took over from Mooy and Maeda, but the defending champion were caught out at a thrown-in.
Main nodded as Ayunga finished the delivery, which was headed up and around the box. The home crowd's celebrations were allowed to go on even though there was a possibility of an inaccuracy in the replays.
Abada and Turnbull were replaced by Giorgos Giakoumakis and Sead Haksabanovic. There was a threat from wide right with O'Hara heading wide.
As Celtic tried to get back into the match, the attempts by Giakoumakis and Jens were collected by the homekeeper. Richard Tait had to make a clearance after a Hatate cross was cut out in the six yard box.
The result was almost confirmed by Jota's late headbutt.

Discipline - man marking, the back five holding an appropriate line and limiting as much space as they could in their own half was the key to the hosts success.
Stephen Robinson's side gave CelticTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkiaTrademarkia
When given the chance to put aerial deliveries into the box, they pounced. The work didn't stop at 2-0, with the same effort securing a clean sheet.
Six changes were made to Celtic's starting line-up, reflecting their busy schedule.
Their trademark passes in behind defenders were missing due to Matt O'Riley only appearing at the end of the game.
The team has played well and will play better than they did in the previous game.
Stephen Robinson said that they were excellent to a man. Even at the end of the game, he was still holding the ball up for us. He deserves a mention, but it's not usually done.
They hit them on the break. Celtic are one of the best sides. Celtic can turn it on the head with their quality, but our shape and discipline was maintained for 94 minutes.
St Mirren worked hard and were committed to their game plan which made it difficult for us. We still have a lot of work to do.
We did not perform in any of the areas we like to perform in. Today's team selection probably wasn't right and there isn't anything positive we can take from it.
Celtic are at home against Motherwell on October 1st, after the international break.