The American sensation is facing a crisis at his new club.

Chelsea headcoach Frank Lampard has thrown a challenge at USMNT star Christian Pulisic as he aims to secure as slot as a starter in his new side. The 21-year-old attacker has failed to break into the Blues' starting eleven but his manager has stated that the prospect lies in a few adjustments.

Pulisic, who became the most-expensive American player of all-time with his $73 million transfer from Borussia Dortmund to Chelsea this summer, is yet to hit the ground running in the Premier League. Despite showing glimpses of his quality, the winger has seen his chances limited, featuring in just six matches for the Stamford Bridge outfit across all competitions.

The former BVB star has not played in a Premier League game for Chelsea since August 31 and, against Southampton on Sunday, he risks missing out on being included in the matchday squad having been made to sit out the Champions League win over Valencia.

Ahead of Sunday's clash with the Saints, Lampard has explained that Pulisic must work harder in order to break into his side.

" I spoke to him [Pulisic] two days before the Grimsby game and was very clear about the standards and we have to give him the fact he's moved country and moved leagues," he said.

"He's as young as all the young players we keep talking about. He's just turned 21, so I think, if anyone is getting too excited about this, they should calm down because he's started five games for us.

"What he needs to do is work, work daily, work to show within the group that he deserves to play as all the players do, so that's what the focus on everyone is."