Celtic came from behind to hold onto their winning start to their Scottish Premiership title defence as St Mirren suffered their first defeat of the season.
It was the battle of the only unbeaten top-flight sides in Paisley as the Buddies looked to continue their blistering start to move top of the table, and they made the perfect start.
Nikolas Agrafiotis made no mistake from the penalty spot after Liam Scales' blatant handball as he attempted to block Chris Mochrie's effort.
The Hoops thought they had hit back when Camilo Duran knocked the ball in from Hyun Jun Yang's cross soon after, only for it to be ruled out for offside after a VAR check.
Callum McGregor, Hussain Hassan and Yang all missed chances before Scales made amends for his earlier mistake when he rose to bullet Mika Baur's corner into the net.
Duran set up Yang to calmly finish beyond keeper Jacob Chapman to complete Celtic's turnaround as they then held firm against a dogged St Mirren who had chances to level.
New signing Shim Mhueka thought he had netted his first goal in stoppage time, but he too was ruled to be offside.
It is five out of five for the champions as they move five points clear of St Mirren at the top of the table.
18: SAVE! Taylor gets a shot away from the edge of the box but Sinisalo saves.
19: PENALTY TO ST MIRREN! Mochrie's strike comes off Scales' arm, and the referee points to the spot.
22: GOAL ST MIRREN! Sinisalo went the right way, but Agrafiotis' powerful effort hits the bottom corner.
29: GOAL CELTIC! Duran with the response for Celtic!
31: NO GOAL! Celtic's celebrations are short-lived as VAR rules out Celtic's equaliser for offside.
40: SAVE! McGregor meets Baur's corner but he doesn't connect properly and Chapman keeps it out.
42: SAVE! Hassan sends in the cross, it eventually lands at Duran's feet just yards out but the Buddies keeper reacts.
48: WIDE! Hassan with a brilliant ball in for Yang, who somehow puts it past the post. What a miss!
51: GOAL CELTIC! Scales rises to head in from Baur's corner. Redemption for the defender.
55: BLOCK! St Mirren almost caught out again. Scales rises to meet another corner, but this time he heads wide.
64: BLOCK! Nygren cuts the ball back to Yang. Ramsay does well to get in front of him and send it off target.
68: GOAL CELTIC! Duran wins the ball back, Yang goes through one-on-one with Chapman and makes no mistake.
74: SAVE! Sinisalo denies Thomas as the Buddies refuse to give up.
86: CHANCE! Thomas misses from six yards. He lunges for the ball and can only stretch and put it over!
90+3: GOAL DISALLOWED! Mheuka slots home but the referee rules it out after being called to the monitor.
Your Site' James McFadden
"Celtic were worthy winners, they deserved to win.
"They had the pressure, they had the possession, they had the chances and took them when they came.
"St Mirren stuck true to what the manager asked from the first whistle through to the last.
"They were open, they do want to take risks and build. They're not building just for the sake of building, they're trying to draw the press. If the press is already on they'll go direct.
"They kept themselves in there and it is brave because if you're that open against a team like Celtic then you can look silly but they didn't tonight.
"A very brave performance. You can see exactly what he [Craig McLeish] wants to do with his team."
Former Celtic captain Jackie McNamara
"A fair result. Credit to St Mirren though, they never gave up and they were always in the game right up until the very end.
"I think when Celtic changed things and the wingers went off they lost a little bit of impetus near the end, but I thought over the piece they deserved the three points."
St Mirren manager Craig McLeish speaking to Your Site:
"I think it shows how far we've come as a group and what we're doing. The boys are in there really disappointed that we've not taken a point from the game, at least.
"We know Celtic are going to carry a threat and they caused us problems at times.
"We still carried a threat ourselves. I think we've had 19 shots at goal, which is really good that we're carrying that threat throughout the game.
"The goals that we actually lose are probably disappointing from our point of view, but Celtic still have other chances and things as well.
"We have to dust ourselves down and go again. The good thing about football, there's always another game around the corner."
Celtic manager Martin O'Neill speaking to Your Site:
"It was a tough evening for us.
"We created some chances in the game, but I didn't feel any phenomenal fluency about us.
"We really dug it out at the end, coming from the goal behind against a team who are in really brilliant form.
"They played splendidly for quite some periods of the game, but we saw it through at the end, which was great."
On losing Hyun Jun Yang to international duty with South Korea, O'Neill added: "He'll be a major blow.
"He puts in so much work for us defensively as well, and he'll be a major blow for us now.
"This is his final game. He leaves now, and he's in sparkling form. He's had a really great start to the season. He took his goal brilliantly, and we will miss him badly."
