Manchester City manager Pep Guardiola says his team must accept that "everything is more difficult" this season as they aim to maintain their high standards.

Premier League champions City suffered a first league defeat of the season against Bournemouth on Saturday, three days after losing to Tottenham in the Carabao Cup by the same 2-1 scoreline.

They will seek to bounce back and maintain their unbeaten start in the Champions League on Tuesday, when they travel to face soon-to-be Manchester United head coach Ruben Amorim's Sporting.

"I know our standards but we've lost just one [league] game. Maybe we are going to lose again in the [next three games in the] Premier League against Brighton, Tottenham and Liverpool," Guardiola said.

"We are just two points behind Liverpool who are a top-class team. We've started well in the Champions League but I know people expect us to win 38 league games and win the Treble every season as these are our standards."

Manchester City have had several first-team injuries to contend with, including losing midfielder Rodri for the rest of the season after the Ballon d'Or winner ruptured his anterior cruciate ligament in September.

Guardiola said his side were in "trouble" after suffering more injuries in the midweek loss at Spurs and they were without key players such as John Stones, Ruben Dias and Kevin de Bruyne at the weekend.

"The reason it is difficult is because we have had a lot of absentees, which can happen in some seasons," Guardiola said.

"To win the Treble, everything has to be on the same page with injuries, but this is not possible this time.

"The teams are very strong and everything is more difficult and we have to accept that. That is the challenge."