So who better placed to survey this season's European Champions League final than Carlo Ancelotti?
Especially as Saturday's match in Milan is a rerun of the 2014 showpiece, when the Italian's Real side beat city rivals Atletico Madrid 4-1 in Lisbon to secure a record-extending tenth crown.
"The Champions League is the best competition in the world," the 56-year-old told CNN Sport. "It's so difficult because there is a lot of competition.
"To win, all the little details have to be right. You have to be in good condition, good physical condition, and you have to be lucky sometimes.
"In my opinion it's a result to reach the final -- that is not easy. Real is playing a tough team like Ateltico, they know each other well.
"I think Real Madrid has more possibility because they have more technical quality but Atletico is really strong and beat Barcelona in the quarterfinal and Bayern Munich in the semifinal."
That Bayern Munich side will be Ancelotti's responsibility in just over a month.
Pep Guardiola's decision to head for the English Premier League to coach Manchester City after three years of domestic dominance in Germany gave Ancelotti a route back into the game.
The three-time Champions League winner has been on an extended break since he was sacked by Real in May 2015, spending a chunk of it in Vancouver, Canada.
But for Real's fans, Ancelotti will forever be known as the man that made history with the Madrid team in that 2014 final, an injury-time Sergio Ramos equalizer prompting a three-goal flurry in extra time.
"Two years ago in Lisbon we won a tough game and I think it will be the same in this final," he said. "I hope Real Madrid can win.
"The whole year all the people were speaking about "La Decima." It was almost like an obsession but it was a great, great motivation for us. It was really special."
The divide in Madrid could not be greater.
Not only is the animosity between the two groups of fans overt, so is the disparity between playing styles and the personalities involved.
Self styled as the "galácticos," Real can lavish around $120 million on a single player, as it did to sign Cristiano Ronaldo, the current World Player of the Year, and Gareth Bale, who put Real ahead in the 2014 final.
Atletico is built around a water-tight team ethic that comes from its combative coach Diego Simeone and its spending power is modest compared to Real, its record transfer fee half that of its illustrious neighbors.
Many pinpoint Atletico's relentless attitude as a factor in that heart-breaking defeat two years ago, the four goals Real scored past the 90-minute mark suggesting it had simply run out of gas.
"When they equalized, we knew it was going to be really difficult for us because of our physical state and we were going to struggle," Atletico's captain Gabi recently told reporters.
"We're in better shape, we're better prepared and many of us know what it's like to play in a Champions League final. You can't erase losing but we have a great opportunity to play another one and make history."
While the six members of Atletico's squad that remain from Lisbon insist they are better prepared, Ronaldo -- Real's star player -- thinks the nous in its ranks could be the key factor.
"A lot of the time experience is very important and in this aspect we've got a small advantage," he said at Real's media day ahead of the final.
"Atlético will be alert as a result of what happened two years ago and I hope the game will be different. Atlético will want to win but we are ready. We're going to play with intensity and I'm confident about a victory."
Ronaldo himself sums up the differences at both ends of the pitch between the two. His 16 Champions League goals this season are as many as Atletico has managed as a team.
The 31-year-old is the competition's record scorer with 93 but carries with him a reputation for being difficult -- a diva -- and hard to manage.
Nonsense, according to Ancelotti.
"A lot of people ask me if it is difficult to manage top talent but it is really easy because they are so professional," he said.
"Cristiano Ronaldo is so successful because he is really serious, really professional. I wrote in my book -- "Quiet Leadership"
-- that usually when we got back at 3am from away games, instead of going to bed he would take an ice bath."
Ronaldo enjoyed a good relationship with Ancelotti but not with his successor, Rafael Benitez -- newly installed as Newcastle United manager.
But after Real's dramatic 3-0 quarterfinal victory over German side Wolfsburg that saw it triumph 3-2 on aggregate, Ronaldo said he "loved" working with the current coach Zinedine Zidane.
The Frenchman spent five years as a player at Real, scoring the goal that won the club its ninth Champions League crown in 2002, and knows all about being its talisman.
He was assistant coach to Ancelotti during that 2014 triumph and the Italian is convinced the club's future is in good hands despite this being Zidane's first managerial post.
"I'm sure he will be the man for the future of Real Madrid," said Ancelotti of the man known as Zizou.
"He has charisma, he knows the club and he started really well to reach the Champions League final. I hope for him he can win.
"He knows well that Real Madrid is a tough club -- if you don't win, history says you will be sacked."