Mauricio Pochettino said it would be "impossible" for him to coach Barcelona in the future as his Tottenham side prepare to face the Spanish champions on Wednesday.
As a player, Pochettino made more than 250 appearances for Barcelona's local rivals Espanyol, helping the club to Copa del Rey titles in 2000 and 2006.
His success in England with Southampton and Tottenham has brought links with some of the giants of European football, but Barcelona is not one that the 46-year-old would consider given his loyalty to the team nicknamed the Parakeets.
"It is something that is more than understood," the Tottenham coach told Marca.
"I have a lot of friends in Barcelona, who are from the Barca team and to whom I have enormous respect, but my way and that of Barcelona are going through different paths, in opposite directions and that would be impossible.
"It motivates me, being a parakeet and living for so many years in Barcelona. Going back to the city is always something nice and playing against Barca, too.
"It is always motivating."
Pochettino praised opposite number Ernesto Valverde for extending Barcelona's footballing ethos beyond the era of players who defined the club for a generation, like iconic midfield duo Andres Iniesta and Xavi.
The Blaugrauna are enduring a mixed spell of form in LaLiga, having drawn two and lost one of their last three matches, but Pochettino said his Spurs players would be going up against a "great team", led by fellow Argentine Lionel Messi - who he still considers to be the world's best.
"We are talking about a great team captained by the best in the world, Leo Messi," said the Spurs boss, who secured back-to-back league wins with a 2-0 victory over Huddersfield Town on Saturday.
"Behind him he has a legion of soccer players that make them a team to fear. Quality everywhere.
"It is clear that now that there is no more Xavi or Iniesta. There are few footballers from that generation and it is normal that Barcelona has been transformed into a different team.
"Valverde has tried to change things, but he has kept the principles, giving nuances to the game of Barcelona, which has been enriched.
"Football is about the players and when you have players as big as Barcelona has been, capable of delivering a philosophy beyond the coach, it is difficult to change them.
"To replace this type of soccer player is impossible. They have been unique, with enormous talent. You can sign players, but they are different and when it comes to showing the football you want to teach, it will always be very difficult to play the game from other times.
"It is a team with great players, determinants and that can beat anyone."