Bobby Lennox will watch the action unfold from his seat inside the arena as part of the Celtic delegation returning to the city to mark their own time as champions in 1967 and wonder why the Spanish club never did attempt to add one more legend to their constellation of stars: Jimmy Johnstone.
Lennox scored the goal that earned the Glasgow club a famous 1-0 win victory over Real in the Santiago Bernabeu on June 7, 1967 - two weeks after they had seen off Internazionale in the Portuguese capital - in the testimonial match that saw Alfredo di Stefano bid farewell to the game.
It would never have happened without Johnstone, though. Prior to splitting the home defence with a superbly-weighted diagonal pass, the winger, socks round the ankles, collected the ball deep inside his own half and ghosted past a handful of players just as he had done time and time again.
Johnstone played the football of his life that night, turning established international players inside-out, executing backheels, slowing the match to walking pace and flipping the ball over people's heads as the 120,000-strong home crowd applauded his every move.
Lennox, insisting it has nothing to do with the 1974 European Cup semi-final that saw Atletico kick Celtic off the park and out of the tournament, will be cheering on Real this evening as he reflects on the golden moment in which he put them firmly in their place.
It only remains a mystery to him that they allowed Johnstone to depart the city limits without signing a contract.
"It was a great game, a real ding-donger, and a great night," recalled Lennox. "They'd gone into the press and said that they would prove they were the best team in Europe, but the boys were great and proved that they weren't.
"Jimmy was great that night, although I did point out to him that it's goals that win games rather than dribbling. I still don't believe that Real Madrid didn't come in and try to buy him. He was magnificent against them.
"Jimmy could have played for any club and could have done anything, but he had to be happy to play his best football and I don't know if he would have been happy anywhere else. Jimmy was asked once what he would do if he was earning £20,000-a-week. He said: 'I'd be dead by the time I was 22.'
"That's the story. I couldn't picture Jimmy Johnstone living anywhere other than where he lived.
"He was really happy in about Celtic Football Club."
Poignantly, Johnstone is of course one of those missing from the get-together being staged in Lisbon involving the members of the 1967 squad and their families.
Jock Stein, Sean Fallon, Neilly Mochan, Bobby Murdoch and Ronnie Simpson will also occupy the thoughts of their old friends and colleagues over the course of this weekend as they enjoy this particular, sun-kissed trip down Memory Lane.
Lennox is particularly thankful to be there after undergoing heart surgery last November.
"I had a triple bypass," explained the 70-year-old. "I feel a lot better now. I wasn't great for a month or two, though. I couldn't believe it at the time because I thought I was a fit wee guy, but I'll get back into shape.
"I'd had angina for years and the pills basically stopped working. I am just grateful for what I have got and meeting all the rest of the boys and wives is great fun.
"The likes of Jimmy, Bobby and Ronnie will be sorely missed, but their names will be mentioned a lot and all the stupid stories will come out.
"When we went to Lisbon in 1967, we were fit, confident and thought we could win the European Cup.
"This time, we have taken our pills and our sprays. If anyone forgets them, we could be in trouble. I just hope we all get back all right."
Stevie Chalmers, who scored the goal in the Estadio Nacional that secured a 2-1 win over Inter and a special place in history, admits there may well be a few tears as the weekend develops and old friendships come to mind.
"The team is like a family and it will be emotional because we've lost a few of the boys," said Chalmers. "Bobby Murdoch was my room-mate. It was his ball across goal that I scored from. I often think about that.
"We will be thinking about wee Jimmy and the way he played as well. We will be thinking about all of them and it is a big thing that their wives come on the trips. It's hard on them, too."