Ronaldo told the Sunday Mirror: "We were under more pressure last year because we had not won the championship for a few years, but there is always pressure to win with Manchester United. I believe we are going to win the League, the Champions League - or both."
He added: "Over the last few years the title has been between Manchester United and Chelsea, but that will change this season.
"Chelsea will miss Mourinho because he is a great manager.
"I know we are not playing the best football at the moment, but I think our top form is coming."
