Chelsea coach Enzo Maresca said his players are still trying to adjust to his style and tactics after they lost 4-1 to Celtic in a preseason friendly in Indiana on Saturday.

Christopher Nkunku's 89th-minute penalty was the only consolation for the Premier League side at the University of Notre Dame.

It was Maresca's second game in charge following a 2-2 draw with League One side Wrexham in California on Thursday.

"Off the ball we need to improve things," Maresca said. "You can see sometimes we confuse when we need to play short and when we need to play a little bit longer but that is part of the process.

"We maintained a high line but when the ball is not under pressure, you need to drop ... We are still confusing some things on the ball and off the ball. It is normal in this moment when we are trying to do something new."

Despite the lacklustre results, Maresca, 44, said his team would be ready for their Premier League opener against champions Manchester City on Aug. 18.