Neil Lennon was attacked by a fan at Tynecastle as Celtic kept their title hopes alive with a 3-0 win over Hearts.
When Gary Hooper scored his second goal in the 49th minute - after Jambos midfielder David Obua had been sent off by referee Craig Thomson before the break for raising a hand to Charlie Mulgrew - a supporter came out the main stand to grapple with the Parkhead boss.
An astonishing melee ensued and the intruder was eventually marched up the tunnel by police but that was not the end of the trouble as some fans in the Celtic section of the ground appeared to fight with stewards and police.
There was more controversy to come when Kris Commons grabbed Celtic's third in the 77th minute, moments after he was booked for simulation.
The Hoops midfielder was sent off for leaving the field of play in celebration as the visitors finished the game one point behind Old Firm rivals Rangers going in to the last game of the season on Sunday.
Willy Aubameyang's equaliser for Motherwell at Fir Park secured fifth place for Kilmarnock with a 1-1 draw.
Steve Jones put Motherwell ahead in the eighth minute when his 20-yard strike caught out Cammy Bell at his near post, but Aubameyang netted from close range three minutes after the break.
A wonderful striker from teenage sensation Nick Ross helped Inverness Caley Thistle beat Hibernian 2-0 in Inverness.
The 19-year-old's volley from the edge of the area, which is a goal of the season contender, bounced in off the underside of the crossbar after 51 minutes. Richie Foran broke the deadlock on 40 minutes when his angled header from six yards went in off the post.