The Blues' top scorer this season netted twice as his side drew 2-2 at Atletico Madrid on Tuesday, booking a place in the last 16 of the UEFA Champions League in the process.
Chelsea were made to work for their point and Drogba has confessed that the looming top-of-the-table Premier League clash with Manchester United may have distracted focus.
But Ancelotti, who has been persistently linked with Atletico's two-goal forward Sergio Aguero despite a transfer embargo, has been delighted with Drogba's performances since he took charge of the Blues in the summer.
"I don't know (if he is the best). For sure, I want to keep him. I don't want to change him for any other striker," said the Chelsea manager.
He added: "I'm very happy with his behaviour and I hope he continues like this."
MikelAnd Ancelotti has been handed a further boost ahead of Sunday's showdown with the Red Devils as midfielder John Obi Mikel has declared himself fit to feature.
The Nigeria international has missed the last three games with an ankle injury but could return to the fray at Stamford Bridge, live on Sky Sports 1 and HD1.
He also has his sights set on featuring for his country the following weekend when they tackle Kenya in a crucial World Cup qualifier.
Mikel said: "I will hopefully start playing again this weekend. I'm also looking forward to helping Nigeria.
"It is very important for us to win. We all have to work hard and simply pray that the result favours us."