When it comes to the Champions League nights, Real Madrid have normalised the extraordinary.

They showed that in their recent semi-final. With 10 minutes left in the second leg, Bayern were 1-0 up at the Santiago Bernabeu. Real were heading out.

Davide Ancelotti had been pestering his father, Carlo, to make one particular substitution.

Jude Bellingham, who regularly makes timely runs into the box from midfield, was tiring. Bayern were concentrating all their energy on defending against the power and pace of Vinicius Jr.

Davide realised the team needed more presence in the box, a player to split the defenders' attention. He looked to Joselu, a player with a tall frame and striker's instinct.

The former Stoke and Newcastle forward had come to Real on a season's loan from second-division Espanyol. Not many would have picked him out as the player to produce some late brilliance. But as a frustrated Ancelotti senior turned to his son on the bench, Davide made his point: "Joselu dai." Dai, an Italian term, means 'come on'.

Carlo relented and told the striker to warm up. Thrown on in the 81st minute, Joselu capitalised on a Manuel Neuer error to equalise and followed it up with a quick second to send the Spaniards to yet another Champions League final. Ten minutes, two goals. The power of one substitution.

Once again, Davide had made the right call. Carlo's son, as Real's assistant manager, continues to be his secret weapon.

How is it that Real continue to reach finals despite apparently not having a clear footballing philosophy?

Davide has made it clear in many interviews that their teams succeed through that flexibility. They adapt according to the situation. There is no set ideology. They may start a game with a 4-3-3 set-up, but it can change many times during a single game.

In an intriguing interview with Corriere dello Sport, Carlo Ancelotti explained: "I don't believe in ideologies like Guardiolismo, Sarrismo... I believe in the identity of the team."

Rather than be wedded to a style of play that requires certain players to ensure its success, the Italian pragmatically builds his tactics around the talents of his individuals.

"A clever coach is one who adapts the game to the characteristics of his players. He would be an idiot if, with a forward like Vinicius, who has a motorcycle under his feet, he did not bet on the counter-attack. Another example: if I have Cristiano [Ronaldo], I look for a way to get the ball to him often, I don't ask him to go back."

Since his return to Real Madrid, Ancelotti has more than ever focused his side on adapting to opponents, creating chaos, forcing errors, pouncing on them.

Bayern Munich were not the first team undone by Real in a fast turnaround.

Much of the success of this approach is down to Davide, who has grown to be a valued asset on the bench. He is the man tasked with challenging his father tactically.

Javi Martinez, the former Bayern midfielder, has played for both Ancelotti and Pep Guardiola.

He described the role Davide has played in his father's continuing success.

"The evolution process never stops and it is more difficult to adapt for older coaches," he said.

"Davide completes Carlo and helps him understand the evolution of football. Davide is incredible: prepared, serious, a great person, like his father."

Once a footballer himself, Davide knew from an early age that he wanted to be a coach like his father. He understood tactics and would have a say on how to organise a team even as a youngster.

A naturally curious boy, if he was interested in something, he wanted to learn everything about it. As the son of one of Italy’s greatest tacticians, Davide became consumed with being the best he could be.

A sports science graduate, he joined his father's staff at Paris St-Germain. At Bayern Munich, he became his father's assistant coach. As he often states, his primary role is to offer his father a different tactical perspective. At Real Madrid, his value to the squad has grown more important.

Davide wants to learn all there is to learn about the game. He watches countless games around Europe, studying the opponents and reflecting on the data gathered on his own players. He oversees training, takes charge of set-piece routines and devises certain patterns of play.

However, his true value lies in his ability to look at specific moments in a game and quickly decide the route to victory.

Take the first league match of the 2022-23 season. Real Madrid had conceded an early goal to Almeria. It took until the 61st minute before they found the equaliser, but they needed a winner.

Luka Modric won a free-kick and Davide was seen giving detailed instructions to incoming substitute David Alaba on the sidelines. Toni Kroos and Karim Benzema stood over the ball, waiting to unleash the set-piece. Davide interjected. Speaking to his father, Davide made the case for why Alaba had to come on right away and take the free-kick.

The set-piece was on the right. It was in the ideal position for one of Alaba's sweet left-footed strikes. The defender scored. The win was secured.

Davide, who speaks five languages, has good individual relationships with Real's players. He can always be seen giving them instructions. He works with them after hours to develop their game.

As one example, take Karim Benzema's defensive positioning at corners. That was something the French striker worked in with Davide, to improve his defensive contribution, to reduce the number of goals conceded from set-pieces.

Aurelien Tchouameni has spent plenty of time after regular training working with Davide to better understand how to receive the ball, how to turn his body and how to adapt his posture, permitting him to play in several positions. This has come especially handy as Madrid lost several centre-backs to injuries this season.

What next for Davide Ancelotti?

By identifying opposition weaknesses and knowing how to shift the momentum of a match, Real have enjoyed some remarkable recent European successes.

The epic comeback from two goals down on aggregate against PSG in 2022? It was started by asking Benzema to apply a little pressure on Gianluigi Donnarumma when the goalkeeper had the ball at his feet. Carlo Ancelotti admitted to having prepared the tactic, aware of the goalkeeper's vulnerability when trying to play out. Benzema forced the error, got a goal, and the whole tie was transformed.

Studying opponents in the hunt for weaknesses has proved to be Davide's forte. He uses his knowledge and data analysis to advise his father on how best to approach the game.

It was he who drew inspiration from Arsenal's approach in the 0-0 Premier League draw against Manchester City in March. He noted how the defensive low block frustrated City. When Real travelled to Etihad Stadium for the second leg of their Champions League quarter-final two and a half weeks later, a gameplan was formed. Ceding possession and playing a defensive minded game allowed them frustrate City. Real still needed a penalty shootout to get through, but they made it.

Davide has shaken off accusations of nepotism, and is now a coach in demand. Just a few days ago, he was linked with the top job at French Ligue 1 club Reims. A decision on his future beckons, but in the meantime, he has yet another Champions League final to prepare for. Will Real win their second European final in three years?