Bayern Munich coach Jupp Heynckes has said Real Madrid should be as wary of Robert Lewandowski as his side are of Cristiano Ronaldo.

As the two sides prepare to meet in Munich in the first leg of the Champions League semifinal on Wednesday, Heynckes said Lewandowski was "always ready to produce top performances."

Ronaldo has scored in 12 straight games, including 25 goals in his last 15 matches.

"I respect Ronaldo immensely -- he has had a superb career," Heynckes told his prematch news conference.

"But you need to play well as a team to win the Champions League, and in Robert Lewandowski we also have a striker who has already scored 39 goals this season.

"He is a very positive player, always ready to produce top performances. One could also ask how to shut out Lewandowski."

Asked whether he would swap the Poland captain, linked with Madrid in the past, for Ronaldo, the coach said: "Bayern is very happy with Lewandowski, so it's not a question for consideration."

Heynckes, whose Bayern won the 2013 Champions League against Jurgen Klopp's Borussia Dortmund, is confident of getting there again.

"We are in a similarly rich vein of form to 2013, and we are working tremendously hard as a team, he said.

"Obviously very tough opposition stand in our way, but I am very optimistic for the two games. For me there are no favourites, but I have a good feeling.

"We are in great form and having an exceptional season and want to crown it by reaching the Champions League final."

Robert Lewandowski is in form for Bayern Munich. PATRIK STOLLARZ/AFP/Getty Images

Heynckes said he believed his in-form players "have a great team spirit" and their willingness "can move mountains."

"You cannot buy the Champions League title. A team has to grow and the players have to respect each other," he said.

David Alaba and record signing Corentin Tolisso are injury doubts, with Heynckes saying he would make a decision about whether to include them in the squad on the day of the game.

Meanwhile, defender Jerome Boateng said Bayern were over the disappointment of last season's quarterfinal loss to Madrid.

"Last year's exit isn't in our minds any more," he said. "We have a great chance to make the final this year, and that's all we're focused on.

"They haven't won back-to-back Champions Leagues by chance, but we are confident.

"It's always fun to play against the best players -- it's the only way you can improve. Ronaldo is an unbelievable athlete -- you can see that with the goals he scores and when he takes his shirt off.

"He has almost no weaknesses and is so good in the air. We'll only be able to stop him as a team."