The England Under-21 international has moved to Stamford Bridge on a seven-year contract. Here is what he will offer Maresca's

A deal to sign Gittens was struck late last month and Dortmund revealed on Thursday that the young winger was on the cusp of signing for Chelsea, who are reported to have paid an initial £48.5 million ($66.2 million) with a further £3.5 million ($4.8 million) in add-ons.

Chelsea have signed Jamie Gittens from Borussia Dortmund on a contract until 2032, the Premier League club said on Saturday. "It feels great," Gittens said. "It's a great feeling to join such a big club as Chelsea. "I can't wait to learn from everyone in the team and to push myself to the max here. It's an amazing feeling."