Holders Celtic edged into the semi-finals of the Scottish League Cup after Leigh Griffiths' 83rd-minute goal earned a nervy win over St Johnstone.

Brendan Rodgers' side are enduring their worst start to a season since 1998 and toiled for much of this match.

However, Griffiths was their saviour for the second time in six days when he turned in from six yards.

It means Rodgers can still win a seventh trophy from seven attempts since taking charge at Celtic.

Celtic finished the match with 10 men after Dedryck Boyata was shown a straight red card, while fellow centre-back Kristopher Ajer limped off with what appeared to be a hamstring injury.

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Confidence lacking, but reward wasn't

Rodgers has spoken at length about confidence in the past few weeks - he knows it's been in short supply for a group of players who had endless supplies of the stuff over the past couple of years.

He mentioned it again ahead of this game and once again it was in short supply at key times.

The first half, for the Celtic fans huddled into both stands behind the goals, was worryingly familiar - lots of side-to-side football and a head-scratching inability to break down a very organised St Johnstone.

It took a full half an hour for the visitors to create a chance and Griffiths should have scored from it. He rose to meet an excellent Odsonne Edouard cross but could only head into the feet of Zander Clark.

Another player usually bursting with confidence squandered an even better chance at the end of the first half. Callum McGregor skipped through on goal from an Olivier Ntcham through ball but the usually dependable midfielder could only fire the ball wide.

After the break, Clark tipped a McGregor toe poke around a post before pulling off an acrobatic save from a fierce Ntcham shot moments later. Suddenly the away support started to make some noise as their side started to turn the screw.

The tempo was up and the swagger was back as Clark was once again forced to save, this time from a long range McGregor strike that was looked destined for the top corner.

Saints remain focused though and they had to. Griffiths broke free and once again should have scored, Clark again saved with his feet.

But he wasn't to be denied. Just like against Rosenborg in the Europa League last Thursday. James Forrest's header was deflected inside the box but when it dropped to Griffiths, he fired low into the net. It was well deserved.