Sir Alex Ferguson has spoken of his belief that Manchester United can emulate the Treble-winning team of 1999, but the manager also expressed his deep concerns that if they were to eliminate Chelsea from the Champions League it would almost certainly cost Carlo Ancelotti his job.

Ferguson is aware that Roman Abramovich is becoming increasingly frustrated by Chelsea's failure to win the European Cup, but he feels it would be unjust if the Russian were to sack Ancelotti.

"It's incredible for Carlo, he won the Double last season. How can Chelsea think of changing such a coach? Carlo is a fantastic guy, a really nice person. There's nothing really between our two teams. Both possess excellent footballers, both have international experience, experienced, good coaches. Really, I don't know where all the criticism comes from."

Ancelotti has won seven of his 11 encounters with Ferguson, and it is nine years since United last won at Stamford Bridge. Yet Ferguson is encouraged by an easing injury situation – Rio Ferdinand could feature at Stamford Bridge – and took the rare step of publicly setting his sights on the Treble as he reflected on the club's position seven points clear at the top of the Premier League, in the last eight of the Champions League and with an FA Cup semi-final to come against Manchester City. "It's 14 games in two months if everything goes our way and, at United, we are used to this kind of thing, which is to our advantage. In the past I have said many times that to win just one trophy would be great. But we have to take the chance of winning all three now. We can repeat the treble of 1999."

Ferguson also talked about José Mourinho's chances of succeeding him at Old Trafford, but the 69-year-old reiterated he had no plans to retire despite the Real Madrid and former Chelsea manager being viewed by many as his long-term successor. "I'm a great friend with José, we often speak of his future. I can understand his desire to come back to England because there is more freedom for a manager here. But it's difficult for me to tell him when this position [at United] will become available."