Bayern host Real Madrid in a blockbuster Champions League semi-final, first-leg, at the Allianz Arena with Ronaldo in goal-scoring form.
The Portugal superstar has scored 15 goals in the Champions League this season, hitting the net in each of Real’s ten games in Europe.
“We can only stop Cristiano Ronaldo as a team,” Bayern centre-back Boateng told German magazine Kicker.
“In front of goal, he’s like a machine.
“You can’t shut him out completely, he always gets his chances in a game, because of the lines he runs and his excellent timing.
“Real base their game around him and it’s important we give him as little room as possible.”
Ronaldo was at his lethal best when Real beat Bayern 6-3 on aggregate in last season’s quarter-finals, scoring five of their goals.
He hit two second-half goals as Real came from behind to win 2-1 in Munich, then bagged a hat-trick in a 4-2 extra-time win in Madrid.
That came after he scored twice in Munich in the 2014 semi-final 4-0 rout of Bayern and hit two more against the Bavarians in the 2012 semis.
“There is a no more complete striker than Ronaldo. Left foot, right foot, header – he is in perfect control of everything he does,” says Boateng.
In his six Champions League knock-out games for Bayern against Ronaldo’s Real, Boateng has lost five of them.
His only success was a 2-1 win in Munich in the 2012 semi-finals when Bayern later progressed by winning a penalty shoot-out in Madrid after losing 2-1 in the second-leg.
“I went through only once against him with Bayern, but twice we have gone out,” says Boateng.
“He also has the best team-mates at Real. Shutting him out is only 50 percent of it, the other players are simply too good for that at this level.”