The Ivorian has a terrific record against the Gunners, scoring 13 times in his 13 games against them, including one in the 2-0 win at Stamford Bridge earlier in the season.
He has been on a poor run of form recently, however, prompting Ancelotti to insist everyone will see a "different" Drogba against Arsenal.
And the Blues boss says Arsene Wenger's side will be cautious ahead of the game given Drogba's remarkable record against them.
He said: "I think they are a little bit afraid of the performance of Drogba, because he's done very well against them.
"If Drogba plays at his best, we'll have more opportunity to win."
Ancelotti, who hit out at the festive fixture list this week, is desperate for his side to beat Arsenal to avoid the gap between themselves and first-placed Manchester United widening.
"We don't want that gap to widen, so it's important to obtain an important result in this game," he added.?