Leigh Griffiths is facing an SFA probe after booting a smoke bomb into St Johnstone fans during last night's League Cup clash at Dens Park.

The on-loan Dundee striker sent the pyrotechnic device back into the away end as Saints fans celebrated their opening goal.

Shaun Rooney opened the scoring before Ali Crawford doubled the Perth side's lead late on to book a place in the semi-finals.

Viral social media footage showed Griffiths firing the smoke bomb into supporters and the SFA are set to review it.

The Celtic striker failed to find the back of the net during the fiesty cup contest and came closest via a free-kick in the second half.

Saints boss Callum Davidson was delighted to secure a spot in the last four of the League Cup as the holders marched on.

He said: “I’m absolutely delighted. It’s one of those that we said we’d do it for the supporters. I thought they were brilliant tonight for us. They kept us going all the way through. 

“I actually thought it was a game where both teams tried to have a go. I thought Dundee, in the first half, probably had the better chances. We probably had the better play but they had the better chances. 

“In the second half we weathered the storm, but once we scored, I thought we settled down, soaked up pressure and then hit them on the counter. 

"It’s a tough game. It’s our local rivals and it’s always going to be tough, competitive, and I thought it was that today. 

“I thought the first goal was always going to be crucial."