Celtic's near year-long unbeaten run in the Scottish Premiership came to an end on Sunday when the Glasgow giants suffered a shock 2-0 defeat by St Mirren.

Goals either side of half-time from Mark O'Hara and Jonah Ayunga condemned the visitors to a first league loss in 39 matches, a sequence spanning 364 days.

Celtic remain top of the table but lead Rangers by just two points after their arch-rivals won 2-1 at home to Dundee United on Saturday.

A bad day on the field for the Scottish champions was compounded by their supporters again disrupting a minute's applause in honour of Queen Elizabeth II.

UEFA opened disciplinary proceedings against Celtic for an anti-monarchy banner displayed during Wednesday's Champions League match at Shakhtar Donetsk.

Ange Postecoglou's decision to heavily rotate his side following their European exertions backfired.

Celtic had scored 25 goals in winning their first six league games of the campaign, but a side featuring six changes struggled to match those standards.

"The performance today wasn't up to our levels and nowhere near where it needs to be," said Postecoglou.

"We didn't perform in any of the areas we like to perform in and have been performing in. There isn't anything hugely positive we can take from today, including the team selection which probably wasn't right.

"There are always reminders we still have work to do. Every team is a potential hurdle."

St Mirren's first home win over Celtic since 2010 catapulted the Paisley club into fourth, with the Buddies joining Real Madrid as the only team to have beaten the Hoops in any competition so far this season.

"Celtic are a top, top side. When playing them, you need people to be brave and get a hold of the ball," said Saints' boss Stephen Robinson. "That's the most pleasing aspect of the game today for me, we played and passed and hit them on the break.

"At any stage of the game, Celtic can turn it on the head with their quality with a moment of brilliance but our shape and discipline was maintained for 94 minutes."

Unlike Celtic, Hearts did not suffer a European hangover after winning in the Europa Conference League in Latvia on Thursday as they beat Motherwell 3-0 to move into third.

Alan Forrest scored twice after Lawrence Shankland opened the scoring at Fir Park to push the Jambos to within three points of Rangers, who they host next at Tynecastle after the international break.