New boss Maurizio Sarri has warned it could take three months before Chelsea are able to perform to their potential.
The Italian believes his inability to work with some of his players following their involvement at this summer’s World Cup has hampered him.
“I am very happy I can work with all my players for the first time tomorrow,” said Sarri after the Blues’ penalty shootout win over Lyon.
“Potentially we can become, in two or three months, a very good team.”
Chelsea are away at Huddersfield in their opening Premier League game on Saturday.
When asked if the game had come too early, Sarri – who succeeded Antonio Conte as Blues boss this summer – replied: “Yes I think so, especially for all of them.”
Sarri started with a largely second team for Tuesday’s pre-season International Champions Cup game, although it did include some players who featured in the World Cup, including Brazil’s Willian, England’s Ruben Loftus-Cheek and Nigeria’s Victor Moses.
Belgian Eden Hazard and France’s Olivier Giroud and N’Golo Kante – the three Chelsea squad members who played regularly for countries who reached the later stages in Russia – were second-half substitutes.