It is clear Guardiola sees the Champions League as the pinnacle - seldom is he more animated than on a big European night.

That image of Guardiola, head in hands on the touchline or wearing a concerned look and throwing arms in the air in frustration, is not an uncommon sight.

Fans will remember Guardiola brought to his knees in the quarter-final against Tottenham in 2019 when Raheem Sterling's last-minute winner was ruled out for offside. They will recall him waving his arms in frustration at the same stage against Lyon a year later.

Defeat in the final by Chelsea in 2021 also stung but when City ground out a 1-0 win in the 2023 final against Inter Milan to win their first European title and complete a historic Treble, fans might have expected that to open the floodgates for more European success.

Instead, they have only won a single Champions League knockout tie since - against Copenhagen - and have lost nine of their past 17 European games.

Four-time Champions League winner Clarence Seedorf told Amazon Prime: "There is no discussion about Pep's quality as a coach. He makes a choice and it is [an attacking] philosophy - he wants to score one more than the opponent.

"But it comes at a high price when you play against the best players in the world at a certain point - [in] quarter-finals and semi-finals.

"I think the defensive part of his game could be improved, but I don't think he's going to change."

With Bayern, Guardiola did not win European silverware in his three-year spell at the club, although he helped them to Club World Cup and Super Cup glory.

In contrast, Guardiola's Barcelona side - which included the likes of Lionel Messi, Xavi, Andres Iniesta and Sergio Busquets - were close to unstoppable in Europe with two titles won by a team widely considered to be among the greatest of all time.

Overall, Guardiola has only lost one final - in 2021 against Chelsea with City - and while there is a perception he perhaps should have won more titles, he remains the joint second-most successful manager in the competition's history, alongside Zinedine Zidane and, in its European Cup days, Bob Paisley.

Only Ancelotti has won more with several managers having won two.

Since his debut season in the Champions League, Guardiola has managed more matches in the latter stages from the quarter-finals onwards than anyone else.

Having spent most of his playing career at his boyhood club Barcelona before going on to manage the Catalan club, Guardiola said City's first-leg tie against Real at the Bernabeu was his 50th time facing his great rival as a player or manager.

He referred to it as his "birthday" but it has ultimately turned into an unhappy occasion for Guardiola, who has now been knocked out of the Champions League by Real five times - once with Bayern and four times with City.

In fact, since City lost the Champions League final to Chelsea in 2021, no other team has eliminated them from the competition.

The fixture has become a regular one in the European calendar with the two sides meeting in six of the past seven Champions League campaigns.

Guardiola has been in the City dugout for all of those and has watched his side progress ahead of the 15-time European champions twice, suffering heartbreak in the other four.

While there is no shame in losing to the European giants, the manner of defeat has often been agonising for City.

There has been a dramatic and stunning extra-time defeat thanks to Karim Benzema in the 2019-20 semis, and a gut-wrenching loss on penalties after a cagey match at the Etihad in the 2023-24 last eight. This time, after a 3-0 first-leg defeat, any hopes of a comeback were quashed by Bernardo Silva's early red card.

Guardiola has been beaten by Los Blancos in the Champions League more than any other manager, with seven losses in total.

Three Champions League titles is more than most managers could dream of and, since Guardiola's first season as a manager, he has made it to the knockout stages of the competition more than anyone else.

But his future in Manchester remains uncertain with his current contract due to expire at the end of next season and there are suggestions he could call it a day at the end of this, his 10th season in charge.

Would Guardiola be content with his European record if it were not to be improved?

There is no doubt his side are in transition with 15 of the 23 players involved in the 2023 Champions League final no longer at the club.

A trophyless season last year - Guardiola's first since his debut season in Manchester - was put down to injuries and new players settling in.

But a second-consecutive season without silverware would perhaps raise alarm bells.

City are still in the title race - they trail Arsenal by nine points but do have a game in hand and home fixture to come against the Gunners. They will also face their title rivals in Sunday's Carabao Cup final and are through to the FA Cup last eight.

But Guardiola has often seemed to covet the Champions League above all else and there will likely be frustration that the competition has brought him more anguish than joy in the past 10 years.