How ‘Rosenior’s son’ Mamadou Sarr joined Chelsea after the ’emotional’ Africa Cup of Nations.

Sarr’s adjustment to life in England was aided by three main factors. First, he spent a month with the team during pre-season in the United States, where Chelsea won the Club World Cup, allowing him to bond with his new teammates.

Secondly, the appointment of Rosenior – whose footballing philosophy Sarr knows well – encouraged the once athletic and tall player to add more power and aggression to his game, both on and off the ball.

Those close to the young defender say he explored the possibility of a loan move to Premier League and Champions League clubs in the summer after the Club World Cup, but Rosenior persuaded him to return to France as vice-captain of Strasbourg while competing in the UEFA Conference League.

They added that if Rosenior had not replaced Enzo Maresca in January, Sarr would have expected to stay at La Minao until the summer.

Third, Senegal’s Africa Cup of Nations win gave him the greatest moment of his career so far, as he started the final as a substitute for the suspended Koulibaly.

Since agreeing to his move to Chelsea, Sarr has taken two hours of English lessons daily and has made significant progress. He still spends much of his time with the club’s French-speaking players, but his older brother also lives nearby in London.

His father Papi offers advice from time to time but remains based in Lyon. He was a steady and supportive influence without being overbearing.

Sarr’s brother Abdo told BBC Sport: “Our father never pressured him.” “In fact, it was our mother who took him to matches and training.

“Our father stood up and let him develop his love and determination for football. He is still the same now – he knows that Mamadou is motivated enough on his own.”

When Sarr returned to Stamford Bridge, he was presented with the ’26th Africa Cup of Nations Champion’ shirt by the team – an emotional moment considering his father was part of the Senegal squad that lost the 2002 final on penalties to Cameroon, with Pape missing that match through suspension.

“It is his best memory in football,” Abdo added. “His father couldn’t play in this final, so it was emotional for all of us. Everyone is proud – and his father’s pride is even greater, because he grew up in Senegal and knows how difficult it is to win this cup.”