Jose Mourinho has warned he will drop his first-team regulars and "go just with the kids" if Chelsea reach a point where they cannot challenge for silverware, saying: "I am ruthless."

Chelsea have made a dismal start to the defence of their Premier League title, winning just two of their opening seven games, and Mourinho has already relegated captain John Terry to a bench role.

Speaking ahead of Chelsea's Champions League game at his former club Porto, Mourinho said he would have no qualms about replacing all of his older players with youth prospects in any competition that they cannot win.

"If the season goes in one direction, that it becomes closed and we can't win [trophies], I will go just with the kids," he said. "It makes no sense, when you have nothing to win, to play the older players.

"I'll play the players we're waiting for instead. I can arrive in a moment where I will look to the kids and say, 'Let's go. Non-stop.' I am ruthless.

"But at the moment everything is open. It's difficult to win the Premier League, but possible. It's difficult to win the Champions League, but possible. It's difficult to win the [domestic] cups, but possible."