Inter enjoyed a morale-boosting victory over Juventus on Sunday.
Ancelotti said: “Juve are strong and experienced, they've made a lot of changes but they still have an impressive strength. Then there's [Coach Max] Allegri's experience, he's used to managing everything.
“Inter could be a surprise this season, everyone had given them up for dead, but not me. That's not because I'm psychic, but because motivation is important.
“They looked like a team in disarray, and instead they came up with a terrific performance against Juve, which means there is quality in the Coach [Frank de Boer] and players."