Chelsea have submitted an official offer for Borussia Dortmund star Christian Pulisic, according to reports.
Despite Chelsea's fine start to the 2018-19 season, manager Maurizio Sarri is keen to strengthen his squad in January and Pulisic has emerged as a top target.
The United States international has long been linked with a move to the Premier League, having starred in the Bundesliga for Dortmund over the past two years.
The Evening Standard say Chelsea spoke to the German club on Friday and asked to sign the 20-year-old when the transfer window re-opens in January.
But it is claimed the bid from the Premier League club was well below Dortmund's asking price, which has been set at £70million.
Pulisic feels his performances warrant a big-money move and is refusing to discuss an extension, with his current deal set to expire in the summer of 2020.
Chelsea are determined to sign a top-class winger with Eden Hazard strongly linked with a move to Real Madrid and Pedro and Willian in the twilight of their careers.
The west London club are optimistic of striking a deal for Pulisic but the Standard say he would rather join Liverpool to be reunited with his former manager Jurgen Klopp.
After losing to Tottenham last weekend in a result that ended Sarri's unbeaten run as Chelsea manager, the Blues returned to winning ways on Sunday, beating Fulham 2-0 at Stamford Bridge.
Chelsea, who are currently third in the Premier League, face Wolves on Wednesday.