Liverpool manager Jurgen Klopp says he feels for Pep Guardiola and the Manchester City players after the club's suspension from Europe.
Uefa have banned City from European competition for two years for "serious" financial fair-play breaches.
City plan to appeal against the ban and have 10 days to take the issue to the Court of Arbitration for Sport.
"It was a shock when I heard it. In this moment I imagine it's very hard for them," the German said.
"I have no idea how these things work - what I can say is Manchester City under Pep Guardiola play sensational football. I've always admired what they do.
"To be honest I feel for Pep and the players because, wow, they did, for sure, nothing wrong. They just played football and sensational football.
"Pep helped the league to improve football."
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City's motivation will be 'immense'
Real Madrid boss Zinedine Zidane expects City's motivation to be "immense" when the sides meet in the Champions League last 16.
The first leg is at the Bernabeu on 26 February, with the return game at Etihad Stadium on 17 March.
"It's a rival who are going to be very, very difficult," said the Frenchman.
"For what has happened, their motivation will be immense.
"I'm not going to go into what happened, what is going to happen.
"It's a team, anyway, who will be a difficult opponent, knowing also how they have been doing in the Premier League. So they will have extra motivation."
City have never been further than the Champions League semi-finals, and have only reached as far as the quarter-finals in their three seasons under Pep Guardiola, who has previously said his time in Manchester will be considered a "failure" if he fails to win the competition.
Winning the Champions League is a more realistic prospect than retaining the Premier League title, with City trailing leaders Liverpool by 25 points in the table.
'The last opportunity to win it'
Former Liverpool defender Stephen Warnock believes that it could be now or never for the current City squad in the Champions League.
"A lot of players will see it as the last opportunity to win it with Manchester City for however many years," Warnock told BBC Sport.
"They will leave the club if they win that trophy because they'll want to win it somewhere else, you get that hunger to win it.
"I think the fans will have a different mindset, you know what it's like when they go to the Etihad, they already boo the Champions League anthem so will that play on the players' minds? But for the players they will be desperate to win that trophy."
Former Everton midfielder Leon Osman believes the ban may galvanise the club.
'Maybe it can inspire them," Osman said. "If they weren't adamant about trying to win it this season, maybe it will give them the extra spirit to win it now."