The Rossoneri are currently languishing in ninth place in Serie A but their Brazilian midfielder says that they are capable of upsetting the Rojiblancos.
The Rossoneri currently sits ninth in Serie A, 31 points behind leaders Juventus, and only managed to beat relegation-threatened Bologna at San Siro on Friday night thanks to a sensational late strike from distance by Mario Balotelli.
However, Kaka claims that Clarence Seedorf's side is in a bullish frame of mind ahead of the visit of Atletico, which is currently locked in a three-way tie for top spot in La Liga with Barcelona and Real Madrid.
"After Friday's victory in the league against Bologna, we are confident and ready for Wedesday," the attacking midfielder said of the last 16, first leg clash at the Giuseppe Meazza during a Twitter Q&A session.
Kaka admitted that the tie is also of the utmost importance to him from a personal perspective, as he has not yet given up hope on earning a recall to the Brazil squad in time for this summer's World Cup.
"I'm doing everything to avoid missing this date," the 31-year-old said. "We'll see if I will be part of the squad."
Kaka, of course, is currently in his second stint at Milan, having rejoined the Rossoneri last summer after a four-year spell at the Santiago Bernabeu with Madrid.
He explained that he never had any doubt that he would end up back at San Siro, as he always held such fond memories of the Italian club.
"I was sure that soon or later in my career I would return to Milan," he said. "The best beautfiul goal in my career was among the 101 scored in the Milan jersey: it was one of the two I got in Manchester in 2007 against United."