Enzo Maresca said on Wednesday that Chelsea are "one team, one squad" despite his policy of making wholesale changes for Conference League matches.
The Italian, in his first season at Stamford Bridge, has effectively been fielding two sides so far this season – one in the Premier League and the other in Europe.
He made 11 changes to the starting line-up for last month's 4-1 win at Panathinaikos, which took Chelsea to the top of the Conference League table after two games.
But speaking on the eve of his team's home match against Armenian side Noah on Thursday, he defended his approach.
"We make changes because we have 24, 25 players, all fit, all good enough to play different competitions," he said.
"The season is so long, we have so many games," he added. "And for sure, all of them, they are going to play Conference League and Premier League games or FA Cup, the next one.
"So it's not, I already said, I can understand that from outside, you can see two teams, but we have just one team, one squad, 24, 25 players, all fit, fortunately.
"And we're going to try to use all of them."
Maresca, whose team are fourth in the Premier League, was asked about the situation of forward Joao Felix, who is yet to start a league game this season.
"I would like to give him more minutes in the Premier League. But I said many times we need a defensive balance, and we cannot play with Joao, Cole (Palmer), Chris (Nkunku).
"I like to put all of them inside the pitch, but then you have to also defend, and you need the right balance.
"And this is the only reason why. But I don't have any doubt that if Joao keeps working well, he's going to find his moment also in the Premier League."
Maresca said the Conference League was tough for Chelsea as they are the favourites.
"We need to be ready technically, but also mentally," he said.
"(Noah) is a team that in their country, they play different shapes. So we don't know how they're going to come here and play.
"Today in football, you can find good players, good squads, good teams and good managers everywhere, not only in the most important leagues in Europe or in the world."