Badstuber sent off on return as Bayern go through

Badstuber, 26, made his first start in the famous red Bayern shirt for seven months, but lasted just 53 minutes before being sent off.

The German champions were already 3-0 up by that stage, thanks to goals by Douglas Costa, Robert Lewandowski and Thomas Mueller.

Even the numerical disadvantage failed to slow the Bayern goal-machine as France Under-21 winger Kingsley Coman added a fourth despite Badstuber's dismissal.

The victory confirmed Bayern will advance to the last 16 as Group F winners, regardless of their final group match at Dinamo Zagreb in a fortnight, for which Badstuber will be suspended.

"It's always important to finish the group first," Bayern captain Philipp Lahm told Sky.

"That brings an advantage in the knock-out stages that you play the second leg at home. It's a good way to finish the year."

Having beaten 3-0 Olympiakos in Greece in their opening European match of the season back in September, Bayern completed the double comfortably.

The hosts hit top gear in the opening 20 minutes at Munich's Allianz Arena as Olympiakos' Spanish goalkeeper Roberto endured a torrid time in conceding three goals.

Just eight minutes had gone when Jerome Boateng's long-range shot was blocked, but Costa won the foot race and slotted the loose ball into the far corner.

Lewandowski doubled the lead on 16 minutes when he converted Coman's cross before Bayern's star-studded squad combined for the third.

Lahm's cross was volleyed across goal to Arjen Robben who headed down and Mueller stabbed home on 20 minutes.

The floodgates threatened to open when Lewandowski fired wide on 24 minutes with Roberto beaten, but the Poland star fired wide of the post.

Robben went off with a leg injury on 33 minutes and Bayern's fortunes took another turn for the worst on 52 minutes when Badstuber was shown a straight red.

Nigeria international Brown Ideye was through on goal when he was brought down just outside the area and Germany centre-back Badstuber was on his way for an early bath.

Bayern barely broke stride and Coman scored with a perfect header that floated over the keeper and into the back of the net on 72 minutes.

He suffered for his art after a heavy clash with Roberto with both players going for the ball.

Both teenager Coman and Joshua Kimmich, 20, who was on for Robben, had late chances as Bayern dropped the tempo, but kept up the pressure while Olympiakos offered little.

Mueller hit the post in the dying stages as the hosts chased the elusive fifth goal.

The defeat means the second-placed Greeks must now beat Arsenal at home in a fortnight to be sure of going through in second place behind Bayern.