The 1980 Scottish Cup final was up there with any of them; he set up the winning and only goal in extra-time, picked up the sponsor’s Man of the Match award at the end of 120 energy-sapping minutes and then lifted the famous trophy aloft as captain.

Alas, the riot that broke out on the pitch after the final whistle kind of overshadowed his outstanding personal display and the result.

“This is like a scene out of Apocalypse Now,” said Archie MacPherson famously in his BBC commentary as Celtic and Rangers fans clashed and mounted police charged them in a desperate bid to restore order.

It had certainly been The Longest Day for McGrain and his team mates before that.

“It was an Old Firm derby, a cup final and the last game of the season so it was a tense occasion,” said McGrain as he looked back on the match, which took place 40 years ago today, earlier on this week.

“It was scorching hot as well. I remember it being a torrid game, a real end-to-end affair. It was quite scrappy if you ask me. I wouldn’t say it was a classic. But it ended up being fantastic for us because we won it.”

The fatigue that Billy McNeill’s men were feeling as the edgy encounter wore on didn’t prevent them from taking the lead after Davie Provan had swung a corner kick into the opposition penalty area in the 108th minute.

“When the cross came over I thought: ‘We need to get this ball out the park’,” said McGrain. “I was tired and the whole team was tired. It was such a hot day. We had everybody up for the corner kick so we could score from it and win the game from there. But I thought: ‘If I lose the ball here the next player behind me is big Peter (goalkeeper Latchford)’.

“It was a comical corner kick. It broke to me outside the box. My first instinct was to get the ball out the park, to waste time. I miskicked it. George (McCluskey) stuck his foot out and it went in. A typical George McCluskey goal! I think Peter McCloy (the Rangers keeper) must have been too busy chuckling at my effort to save it!”

The shameful events that unfolded after referee George Smith brought an end to proceedings were no laughing matter.

“It was a great moment to be presented with the trophy,” said McGrain. “We had just beaten our greatest rivals after extra-time, our side of Glasgow was going mental. We were looking forward to going out onto the park to celebrate with our fans. I looked out and saw a few people on the park. I thought: ‘Well, I suppose that’s allowed in the circumstances’. But all of a sudden there were 200, 300, there.

“When we went down to the stairs to the pitch side we were told we couldn’t go out on the park to do the lap of honour. We didn’t know what was happening. A policemen came over and said: ‘It’s a battle out there’. It was the right decision. There were too many arms and legs flying about. It wouldn’t have been safe.

“When we came out of the ground there was a lot of police running about chasing people. But we got on the bus with the cup, not giving two hoots about anything. We were in our own world. We weren’t really aware of quite how bad it was. By the time we got back to Celtic Park, though, we had heard on the radio what had happened, how many people had been arrested.”

It was an unfortunate way for Bobby Lennox to bow out at Celtic. The Lisbon Lion, who had come on for Johnny Doyle in the second-half, picked up his 26th winner’s medal that afternoon. But the legendary striker was denied the opportunity to say a farewell to the fans and receive their appreciation for all of his heroics over the previous 17 years. McGrain felt for his friend.

“Bobby is the best guy I have ever met in football,” he said. “He is a nicest man you will ever come across. I played with him from the minute I broke into the team until he left. He was such a great professional. He loved the game.

“He always had a smile on his face Bobby, good, bad or indifferent. He had a great sense of humour. It was a shame for him I suppose. But at the end of the day he got the medal and he got the bonus. I am sure he was quite happy with that.”

McGrain was pleased for McNeill. The European Cup-winning skipper had succeeded Jock Stein two years earlier and lifted the Premier Division title at the end of his debut season in the dugout at Parkhead with a famous final day win over Rangers. But that was his first Scottish Cup triumph as a coach. “It was great for Billy to have done that as a player and then as a manager,” he said.

The riot, the worst in Scottish football in 70 years, led to 210 fans being arrested and 100 people suffering injuries, many of them serious. It also resulted in alcohol being banned from Scottish football grounds, an embargo that remains in place four decades later.

It hasn’t stopped the Celtic players of today growing accustomed to the taste of champagne in the last few years.

McGrain has sympathy for Scott Brown, Callum McGregor and Odsonne Edouard just now. They have been denied the chance to win a record-equalling ninth consecutive Scottish title and complete a fourth straight domestic treble by the coronavirus pandemic and football shutdown.

Neil Lennon’s charges had been due to take on Aberdeen in the Scottish Cup semi-final when the game was suspended in March and could potentially have been taking part in the final yesterday.

“The chance has been taking away from them,” he said. “I am sure it will get finished later in the year when football starts up again. But going to Hampden in May to play in the Scottish Cup final is a great tradition and they have been denied that. Still, they have got to give them the Premiership. I think they deserve it.”

McGrain turned 70 at the start of this month and his birthday celebrations were curtailed somewhat by the Covid-19 outbreak and social distancing restrictions.

However, the Celtic great, a world-class footballer who overcame diabetes and a fractured jaw during his playing days and has made a full recovery from the minor heart attack he suffered six years ago, is meeting the challenge head on.

“It is hard,” he said. “It is a horrible situation. But you have just got to deal with it as best you can. I am okay. I still get out for walks, nothing too strenuous.”