The 29-year-old Ballon d'Or winner, who has scored 34 goals in 32 games for Real this season, has missed the last three Spanish league matches through suspension.

Ancelotti said the midfield star was "highly motivated" for the last 16 clash at the Veltins Arena having scored nine goals in five European games this season.

"He's really wanted to play, he was not happy about not being able to do so," said Ancelotti.

"He's done very well in training.

"He is in optimal physical and mental shape."

Unbeaten in their last 26 matches in all competitions, Real are eager to progress having reached the Champions League's semi-finals for the last three seasons.

"I do not have to say much to motivate my players because they want to play a leading role in all competitions," said the 54-year-old Italian, who won the European Cup twice as a player with AC Milan and its successor the Champions League a further two times as coach of Milan.

"The Champions League is the most prestigious, but also the most difficult competition.

"There is no doubt that we are in a very good shape and we want to continue our good run."

Madrid have an awful record in Germany, prevailing just once in 24 previous away matches against Bundesliga opposition and losing 17 times.

That includes a 4-1 drubbing at Borussia Dortmund in last season's semi-final first leg when Robert Lewandowski hit all four goals.

Schalke are fourth in the Bundesliga and having been guilty of erratic form in the first half of the season, they won their first four games of 2014.

Ancelotti singled out Schalke's rising midfield stars Max Meyer (18) and Julian Draxler (20), who is on the verge of returning from a foot injury, combined with proven stars Klaas-Jan Huntelaar and Kevin-Prince Boateng.

"They have very good young players like Draxler, although I do not know if he will play tomorrow, and very experienced players like Huntelaar or Boateng," said Ancelotti.

"It's not a spectacular team, but they have a very effective, solid game.

"I expect an intense match in which Schalke will give everything."

Ancelotti also said Welsh winger Gareth Bale is set to start, "he plays when he's fit", while Schalke coach Jens Keller has said his side will not be overawed by star-studded Real.

"We want to pull off a small miracle. We're not just going out there to swap shirts with Real's stars," said Keller.