Kalac is currently keeping Dida out of the Rossoneri first XI and is relishing his spell in the spotlight.

"Now I am the first choice and I am very happy. Sooner or later there will be an opportunity for (Dida) again. After that we will see what happens," he told Gazzetta dello Sport.

"At the moment I am in top form. I have no aches or pains and I am training as much as possible."

The 35-year-old Australian, nicknamed 'Spider' for his lanky appearance, produced a wonder save to deny Alessandro Gamberini a late equaliser in the Rossoneri's 1-0 victory over Fiorentina last weekend.

The victory saw the Diavolo move up to fifth place and could prove crucial in the race for fourth spot and Champions League football next season.

"The win was fundamental. After the game I enjoyed a few beers," he admitted before describing the time spent waiting for his chance to shine.

"The role of goalkeeper is one that is different from the others. You can't simply alternate between the reserve and the first choice.

"Coach (Carlo) Ancelotti's motives are logical. Sometimes I have understood his choices and sometimes I haven't but that is part of the game. Sooner or later the opportunity arrives."

With Kalac in fine form, Ancelotti will divert his attention to the other end of the field with Milan currently experincing several injury problems in attack.

Brazilian stars Kaka and Alexandre Pato are sidelined, meaning the hosts will likely start with Filippo Inzaghi and Ronaldo.

Marek Jankulovski has recovered from a lengthy spell on the sidelines and could replace Paolo Maldini at left-back. Gennaro Gattuso is injured so Ancelotti will choose between Emerson and Christian Brocchi to fill his boots in midfield.

Siena's promising young winger Paolo De Ceglie is confident the Robur can do well against the Milan giants.

The Bianconeri pulled off a major upset last weekend with a 3-0 home thumping of title challengers Roma.

"Everyone put in excellent performances last Sunday because to beat Roma 3-0 is no easy task," De Ceglie told www.acsiena.it.

"It will be important to travel to Milan with the same attitude. If we go with that same mentality we will be able to do well," insisted the youngster.

"They have a number of champions and if they are missing one or another player there is always a strong alternative in their place.

"The only thing we must remember is that we are Siena and that the reality is we are fighting for survival and therefore we must go there with humility and the maximum determination."

Siena coach Mario Beretta looks set to make just one change to his starting line-up as Tomas Locatelli is once again available so he will replace Houssine Kharja, despite the Moroccan's impressive performance against Roma.

Daniele Galloppa is unavailable through injury and could be joined on the sidelines by Christian Rigano if Beretta decides not to risk him after he picked up a slight muscle complaint this week.