Marc Bartra played alongside Ousmane Dembele at Borussia Dortmund last season Getty

Barcelona fans must be patient while Ousmane Dembele, a £135m ($176m) summer signing from Borussia Dortmund, settles in at the club, former Blaugrana defender Marc Bartra has said.

Dembele signed a five-year contract with Barcelona after joining the club as a replacement for Neymar last month, becoming the second-most expensive footballer in the world in the process.

The France international scored 10 goals for Dortmund last season, helping the Bundesliga side win the German Cup and reach the quarter-finals of the Champions League.

Bartra, who spent six years at Barcelona before joining Dortmund last summer, described the 20-year-old Dembele as a "very talented" player who can have a bright future at the Nou Camp.

"He is a very good player, he can destabilise opponents," the centre-back was quoted as saying by ESPN. "He is very talented... but patience is needed.

"He has only played one year at Champions League level. He is going to bring a lot of joy but you need to be patient."

Dembele joined Dortmund from Rennes last summer on a five-year deal after being voted the Ligue 1 young player of the year. He is expected to make his Barcelona debut in the Catalan against Espanyol on 9 September.

Mikel Merino, a former teammate of Dembele at Dortmund, said he expected the young striker to successfully adapt to Spanish football.

"I'm very fortunate to be a friend of his and I know he is going to do great things at Barca," Merino stated. "Perhaps at the beginning it will take him so time but in the long term, I trust him 100%.

"He is a great player. He has magic in both legs and a spectacular change of rhythm. At any time he can change a game.

"In the end, that is what you pay for. He will change a game in one play. He takes the ball and he wins the game on his own."