Manchester City chief executive Ferran Soriano believes Pep Guardiola is the best coach in world football, but admits it is hard to argue with Zinedine Zidane's record at Real Madrid.
Guardiola won five major trophies in his first three full campaigns at Etihad Stadium, including a clean sweep of domestic honours last season.
City look unlikely to retain their Premier League title, trailing leaders Liverpool by 14 points after a dramatic 3-2 defeat to Wolves on Friday.
Zidane has come under scrutiny since returning to Madrid, despite an incredible first stint at the club that saw him win three successive Champions League trophies.
And while Soriano agrees with Zidane's recent sentiment that Guardiola is the finest coach around, the City CEO has spoken of his admiration for the France legend.
"In the case of Zidane, the results speak for themselves, as in the case of Pep," he said at the the Globe Soccer Awards event.
"There are all the titles he has won in La Liga, the Bundesliga, the Premier League.
"For me, Guardiola is the best coach in the world because he is our [coach]."
City have never won the Champions League and face a huge challenge to be crowned European champions this season, having been drawn against Madrid at the last-16 stage.
The first leg is to be held at the Santiago Bernabeu on February 26 and Soriano believes there is very little between the two teams.
"You look at them and wherever you look - the quality of the players, the money invested, the salaries we pay - these are two great teams that are very even," he said.
"It is unlikely that one team is far superior to the other - it will depend on how these two games take place.
"As usually happens in the Champions League, the tie can depend on a small detail, a defensive mistake or a referee error, which can be decisive."
Asked how the sides compare in terms of style of play, Soriano added: "You usually insist on the importance of City's style of play, while Real Madrid's style is usually winning no matter how.
"With Zidane they have won three Champions Leagues in a row. That's the reality. They have won three Champions Leagues in a row with Zidane and four in five years. Discussions about the style of play die when the data is exposed.
"I talk about what concerns Manchester City, where we play a certain style of football, but we do it because we believe in it and also because we are doing well, because when we don't play well we usually lose.
"Ours is a way of looking at simple football: we have to play our way, and we can execute it in different ways, but the style, the fundamentals, have to be the same so that we do well.
"We can never lose that essence. Maybe other teams can play in several different ways, but not us."