He told The Sun: “I keep saying that I don’t believe anyone can do it. Even when Chelsea were in a position to do it last season, I still didn’t think we could.
“Manchester United were out of the Carling Cup so even when they were doing well in the Champions League, Premiership and FA Cup, they couldn’t do the Quadruple.
“One day it may happen again like with Manchester United winning the Treble eight years ago or with Porto four years ago, maybe with other teams in Europe — but I don’t think it’s possible now.”
He continued on his team’s chances: “I believe Chelsea have the best players in the world — and that’s the way I work.
“I believe to win is to be the best and I will always believe in my players. Who should win the Golden Boot this season? Drogba.
“There will be other players in the frame like Kaka, Ronaldo or Messi, but for me it’s Drogba.
“My players will always be the best players in the world. Who are the candidates to be the best team in the world? Chelsea, always Chelsea. That is my philosophy.
“Everyone has to improve, the club, Jose Mourinho, the players.”