There were a few yellow warnings flying around yesterday but it was a red alert that blew Ayr United’s William Hill Scottish Cup ambitions off course at stormy Somerset Park.

Aaron Muirhead’s reckless lunge on 26 minutes saw him sent off with the match evenly poised at 1-1. The Met Office should have probably issued an advisory to the Ayr dugout right then because within a few seconds of that ordering off, St Johnstone had forged ahead and took control of the tussle. It wasn’t the best of days for Muirhead. St Johnstone’s equaliser came from a deflection off him.

“It’s so close to the first yellow that it’s stupid,” said Ayr manager Mark Kerr of Muirhead’s rush of blood. “You’ve got to just hold back a wee bit and I think Aaron knows that. It’s disappointing after the start we made. We set up to attack with three players up top and then when we lost the goal to make it level it didn’t rock us as we went on the front foot again. But the sending off has really set the game up to be in St Johnstone’s favour."

This was always going to be a treacherous trip for the visitors and Ayr wasted no time in flinging a few more nails down on the road. Only four minutes had passed when a tidy move led to Aaron Drinan sliding a tidy finish into the net.

The cup upset was off and running but it was brought to shuddering halt amid a 10 minute spell of toil and trouble for the hosts. On 17 minutes, Callum Hendry and Muirhead both rose for a cross and it appeared that the Ayr man diverted it into his own net. Having then picked up a yellow card a few minutes later, Muirhead clattered Liam Craig and was sent off.

Within 60 seconds of that dismissal, a wounded Ayr were dealt another hefty dunt when St Johnstone edged ahead. There was no doubting the scorer this time as Hendry got on the end of Ralston’s cross and plonked in a fine header at the back post.

St Johnstone continued to pose plenty of menace in the second half and had chances to put Ayr to the sword. Wotherspoon performed a nice little twist and turn in the box but his shot was well saved by Doohan. Stevie May then conjured a neatly floated chip which evaded the keeper but clipped the post before Ayr had a final chance to salvage something only for Drinan to slice wide.

“I think Ayr will feel a bit unlucky as they started the game really well,” said the St Johnstone manager, Tommy Wright. “Once it settled, we got the equaliser and were in control and then the sending off happened. For us to score straight after that was a big blow for them. Both sides deserve a lot of credit, the conditions were horrendous.”