PARTICK THISTLE have launched a probe into how rival fans ended up in among home supporters at Firhill on Wednesday night.
The Hoops won the Premiership title with a 5-1 derby triumph but trouble erupted after the game as fans invaded the pitch, while smoke bombs and flares were also let off during the match.
A number of rival fans were able to purchase tickets for the Jackie Husband Stand and Main Stand and a Thistle statement said: "Obviously [Wednesday] night was not the type of atmosphere we expect or encourage at Firhill.
"We will be closely reviewing our matchday operations and sales procedures to help ensure that a similar situation never happens again.
"As part of the review process we will be liaising with supporters' groups to gather feedback, as we continue to try and improve the matchday experience."