Manchester City face a serious blow as fears grow at the club that Benjamin Mendy faces a lengthy absence due to a knee injury.

Pep Guardiola’s team have made an impressive start to the season after winning eight of their nine matches so far, with Mendy featuring in five of the victories. Yet the France defender was forced off from Saturday’s 5-0 win over Crystal Palace and despite City initially being optimistic that Mendy’s problem was not serious, the left-back will now fly to Barcelona to see specialist doctor Ramon Cugat on Thursday.

Mendy was taken off against Palace in the 29th minute after a tackle with Andros Townsend but on Monday Guardiola discussed the possibility of a late fitness test regarding his availability for Tuesday’s Champions League group game with Shakhtar Donetsk at the Etihad Stadium. City won 2-0 but Mendy did not feature after the club’s medical department ruled he needs further examination.

After the win over Donetsk, Guardiola said: “Our first impression [is he] will be a little bit long, out of the picture, unfortunately for us. I don’t know, we will wait until Thursday, but I am pretty sure it will be longer than we would like, unfortunately.”

Some reports on Wednesday suggested that the former Monaco defender has ruptured his anterior cruciate ligament, although Mendy himself dismissed that on Twitter.

Your bio says journalist so why you speak like graduated doctor ? no one has test to see if ruptured ACL or not, even I dont know lol 🤷🏿‍♂️ https://t.co/6jMVtELpB6 — Benjamin Mendy (@benmendy23) September 27, 2017

Mendy, bought for around £52m in the summer, has been pivotal in City’s flying start. A prolonged absence would weaken Guardiola’s defensive resources as Vincent Kompany has again been ruled out with a calf injury. The manager can call on Danilo, another summer purchase who can play on the left, though against Shakhtar he preferred Fabian Delph. His other options might be to operate a wingback system featuring Leroy Sané or Raheem Sterling.

Cugat has previously treated Gabriel Jesus, Vincent Kompany and Kevin De Bruyne, with Guardiola particularly trusting of him. Of Delph’s display against Donetsk Guardiola said: “I have a theory - midfield players, when they are intelligent, can play everywhere because they understand the global situation.

“He played an amazing game. I am so happy for him. Last season he was injured a lot of the time and when he was fit maybe I didn’t count too much on him. That was my personal regret. He deserved more minutes.”

City travel to Chelsea on Saturday for their seventh Premier League match. The encounter with the champions should offer the sternest test yet of their credentials.