Chelsea's midfield has been accused of lacking creativity - something Pirlo would surely have provided.
"I tried to get Andrea Pirlo to join us when I arrived. I wanted to play him in central midfield. He's 32 now but doing very well at Juventus. He would have been good for Chelsea," Ancelotti told the Daily Mail.
"But that season we built a good identity of play, which I think Roman was happy with, and while going out in the last 16 of the Champions League was a disappointment I think it was the catalyst for what we then achieved. There was a fresh determination that propelled us towards the Double.
"What happened the next year can happen after a very good season. We started well but then we suffered some injuries to key players. To Lampard, to Terry and to Essien. Drogba had malaria. It was a difficult period and when we started to lose some games we suffered a loss of confidence."