Guardiola spoke of how highly he rates Hoffenheim counterpart Julian Nagelsmann, dating back to their meetings when the Catalan was in charge of Bayern Munich.
Hoffenheim's efforts in their 3-2 defeat to Shakhtar Donetsk last time out in the Champions League, despite being down to 10 men, gave Guardiola a newfound admiration for their play.
"Hoffenheim against Shakhtar was one of the most incredible games I watched as a spectator in the last years," Guardiola added, having studied a recording of the match this week.
"They were incredible how they created, how they did it – even with 10 players for 30 minutes, and they lost!
"It was fascinating watching that game. My admiration and point of view of Hoffenheim has increased. I know about Julian Nagelsmann and his team and I realise how tough it will be."
Manchester City host Hoffenheim in the Champions League on Wednesday evening.