Bayern join Borussia Dortmund, Werder Bremen and Hertha Berlin in this year's semi-finals, which will be played on April 19-20.

This is the seventh straight year Bayern have reached the last four having lifted the trophy a record 17 times.

Pep Guardiola-coached Bayern had few problems at second-division Bochum and should have won by more after Thomas Mueller had a first-half penalty saved.

"Before we scored the first goal, it wasn't easy. Bochum played well and it's always dangerous in the cup," said Lewandowski.

The Poland hot-shot gave Bayern the lead on 39 minutes with a fierce shot from the right.

Bochum were reduced to ten men when defender Jan Simunek was sent off for bringing down Arjen Robben on the edge of the area on 43 minutes.

"I think that was a dive (from Robben) and it wasn't a red card," Bochum coach Gertjan Verbeek told Sky.
"You can't win with 10 men against Bayern Munich, but we worked unbelievably hard."

But Robben was adamant he was brought down.

"He was the last man, it was a clear foul. Those are the rules and, besides, the game was decided after that," said Netherlands captain Robben. 

When the resulting spot-kick was eventually taken, Mueller's weak penalty attempt just before the break was saved by Bochum goalkeeper Manuel Riemann.

But Bayern made sure of their place in the semis when Thiago Alcantara converted Mueller's superb cross on 61 minutes.

Lewandowski then added their third just before the final whistle to claim his 29th goal in all competitions.

Hertha Berlin ended their 35-year wait to reach the semi-finals as Japan midfielder Genki Haraguchi sealed a 3-2 win at second-division side Heidenheim.

The hosts took an early lead when defender Arne Feick was left unmarked from a free-kick to head home on 10 minutes.

But Hertha's Vedad Ibisevic netted twice to put Berlin 2-1 up after 21 minutes as heavy snow fell in southern Germany.

Haraguchi scored the third when he beat two defenders on a mazy dribble before beating the goalkeeper on 58 minutes.

There was a nervous final few minutes as Heidenheim pulled a goal back when Marc Schnatterer netted a late penalty.

Hertha are now just one game away from a home cup final at Berlin's Olympic Stadium on May 21.

The last time Hertha were in the last four was in 1985, almost a decade before winger Mitchell Weiser, who set up both of Ibisevic's goals, was born.

"We got off to a bad start, but we ended up dominating. Now we want to reach the final," said right-back Weiser.

On Tuesday, Pierre-Emerick Aubameyang claimed his 30th goal of the season as Dortmund won 3-1 at VfB Stuttgart.

Gabon striker Aubameyang and Germany winger Marco Reus, who have provided 45 of Dortmund's goals in all competitions this season, netted before Henrik Mkhitaryan claimed their late third.

Veteran Claudio Pizarro helped seal Werder Bremen's 3-1 win at ten-man Bayer Leverkusen by creating and scoring a goal in their shock victory.