LEIPZIG, Germany -- Pep Guardiola says his achievements will never be enough for some of his critics even if he wins the Champions League with Manchester City.

Guardiola has won a clean sweep of domestic trophies since taking over at the Etihad Stadium in 2016 but has not won the Champions League since lifting the trophy with Barcelona in 2011.

- Stream on ESPN+: LaLiga, Bundesliga, more (U.S.)

He will start another campaign in the knockout rounds when City face RB Leipzig in Germany on Wednesday but the 52-year-old believes that for some people, he will always be a failure.

"I would say that if my career finishes tomorrow, literally tomorrow, I would be more than blessed and grateful for what I have done with Barcelona, Bayern Munich and here, in Europe and in other competitions," Guardiola told a news conference at Red Bull Arena on Tuesday.

"I could never have expected to have the career I have had in a short time. Not just for the success we had, but also the way we play -- I love it. I could not ask for more. We want to do our best and get to the quarterfinals but what is going to happen is going to happen. At the end, destiny is already written.

"Sometimes we have been close, sometimes not. I have the feeling that what we have done, all of us, is going to fail. Whatever I have done personally in the past or in the future, I am going to fail. Nothing will be enough."

City have reached the Champions League quarterfinals in each of the last five seasons with the last exit in the round of 16 coming against Monaco in 2017.

Guardiola is preparing for his last-16 tie without Kevin De Bruyne and Aymeric Laporte, who have both been left in Manchester because of illness.

"It is what it is, unfortunately during a season sometimes it happens," added Guardiola.

"Kevin didn't feel good right after the game in Nottingham at the weekend and Ayme did not feel good yesterday. Other players are going to play. It happens sometimes.

"Right after the draw I knew it, I felt it -- that they [Leipzig] would be a really tough opponent. From my experience, we should be confident against any opponent but the reality is completely different."

RB Leipzig, meanwhile, head into the tie having lost just once since September. They sit fifth in the Bundesliga table and beat City in the group stage last season.

Former Chelsea striker Timo Werner is set to start but France forward Christopher Nkunku, who has scored 17 goals this season, is struggling with injury.

"Christo could only take a little part in the game [against Wolfsburg], but he reacted on the strain against Wolfsburg so it's clear he won't be a starter and we will see over the next 24 hours how he develops," said RB Leipzig manager Marco Rose.

"We want him to be available but we don't want to take any risks. We have a lot of matches coming up and we will see how he is."