Scott Sinclair's Motherwell bust-up with a groundsman after Celtic's 5-2 victory was allegedly caused after the winger posed for a photo with a supporter.

Sinclair and the Motherwell staff member became embroiled in a heated argument after the game at Fir Park.

One social media user hailed the forward after the incident, however, claiming it was sparked after he snapped a selfie with her little boy on his birthday.

Posting on Twitter, the user shared the picture, saying: "Thank you so much for coming over and having your pic taken with my birthday boy after today’s match. 

"He was so happy! Proper gentleman .... apologies for what happened to you after you took your time to do this kind deed though".

The woman also added that the heated confrontation was an isolated incident and not an indictment of Motherwell who treated the fans with respect.

READ MORE: Liam Grimshaw says Motherwell will stay on the offensive after Celtic defeat

Former Rangers striker Gordon Dalziel had told on Clyde Super Scoreboard how Sinclair and the groundsman were reportedly "ready to go for each other", and that Sinclair had "refused to let it go."

Celtic won 5-2 thanks to goals from Kris Ajer, Leigh Griffiths, James Forrest, Odsonne Edoaurd and Ryan Christie.

Sinclair came off the bench.