"It would have been a mistake for him if he came and he wanted to go to Chelsea with (new manager) Maurizio Sarri".
'I'm not disappointed, ' Guardiola said. If they are exhausted and they don't want to fight for the Community Shield, play at Arsenal, then stay on holidays.
'So it is important that English football has received an exceptional player and at the end if they want to come, it's better they come. "We are so happy to have him here".
Mahrez played 72 minutes despite a game riddled with frequent changes, and he was closest to making a breakthrough for City with a 20-yard free kick that was brilliantly tipped over the bar by Dortmund goalkeeper Marwin Hitz.
Hart, who has been at the club since 2006, was one of the first players to be ruled out of contention for inclusion in Guardiola's first-team plans when he arrived at the club two years ago. "He is training like a young guy of 18 years old".
He was first loaned out to Serie A side Torino in 2016/17, before spending a year at West Ham while Guardiola's men romped home to the title last term.
The majority of Guardiola's squad are on holiday after their World Cup exploits but new signing Riyad Mahrez made his first appearance for the club against the Germans in a youthful lineup.
Former City youngster Jadon Sancho, who joined Dortmund last summer, and his quick feet set up another chance for Dahoud, which Hart beat away.
The former Wales global told the newspaper: "He's been a top player, he's done a great job at Leicester".
Guardiola added: "He has to improve his game, try to keep the levels he showed last season. I can't say why certain decisions were made".