Peterborough United midfielder Kieran Sadlier played against Celtic while he was with St. Mirren during the 2014/15 campaign.
Peterborough United midfielder Kieran Sadlier has told the Halifax Courier that playing against Celtic was one of the toughest tests he has faced so far.
The young midfielder has represented the likes of West Ham United and Posh during his burgeoning career to date, but he has never found the going more difficult than he did when playing against Celtic.
Sadlier was playing for St. Mirren last season, when he took on the Bhoys, and he was impressed by the quality in their squad.
“I made my first start against Celtic and did really well," he said. "That was a good experience, but one of the hardest games I’ve played.
“Unfortunately we ended up getting relegated, but I can use what I learnt there."
Sadlier's St. Mirren team ended up losing 2-0 to Celtic in April 2015, with Celtic strolling to success on the day.
The Bhoys scored goals through James Forrest and Stefan Johansen, and it was a win which virtually ensured that they would win last season's SPFL title.
Sadlier is now playing for Peterborough, and he has made just one appearance for Graham Westley's side so far, against Charlton Athletic in the Capital One Cup.
The technically astute midfielder is currently on a loan spell at Halifax, where he played in their last three games.