Bayern Munich matched their 5-1 thrashing of Arsenal last month to inflict a 10-2 aggregate pummelling upon embattled boss Arsene Wenger at Emirates Stadium.

It meant a seventh consecutive last-16 exit for Arsenal, who had Laurent Koscielny sent off after Theo Walcott rewardrd a spirited first-half display with the opening goal.

Robert Lewandowski won and converted a 55th minute penalty as Koscielny was dismissed and, as at the Allianz Arena, Arsenal collapsed in the absence of the French defender to suffer the heaviest aggregate defeat inflicted upon an English team in Champions League history.

Wenger was the subject of fan protests asking him to step down both outside the ground and at the site of Arsenal's former Highbury home before kick-off and the sight of Arjen Robben and Douglas Costa picking off his feeble defensive line before Arturo Vidal added a late brace heightened the sense that his race is run.

Carlo Ancelotti's Bayern are still in contention to repeat their 2013 treble, standing in stark contrast to Arsenal and Wenger as they stagger from one disappointment to another.

Alexis Sanchez returned to the hosts' starting line-up three days after being benched for the 3-1 defeat at Liverpool amid widespread reports of a training-ground row.

The Chile star was set to line up at centre-forward but Danny Welbeck was taken ill during the warm-up, meaning a reshuffle with Olivier Giroud coming in to lead the line.

Sanchez's commitments to his hastily assigned defensive duties on the left was tenuous at best during the opening stages as Bayern found joy down that flank – albeit after the action was delayed by the away fans throwing vast amounts of toilet roll on the field.

Visiting goalkeeper Manuel Neuer was out to thwart Walcott after the England winger sprung the offside trap, while Giroud grappled with Mats Hummels to glance wide in the 13th minute.

But Neuer was caught out by a rasping Walcott strike that he could only punch into the roof of his net.

Xabi Alonso was fortunate not to be punished for an ill-judged challenge on the goalscorer before the 27-year-old attempted to repeat his earlier finish by thrashing Shkodran Mustafi's throughball into the side-netting.

Lewandowski should have restored Bayern's four-goal aggregate advantage but pulled Robben's chipped pass wide on the volley and they went in behind at the break.

Early in the second period, Mustafi fizzed another fine low pass towards the Bayern box, although Giroud could not get over Aaron Ramsey's chipped cross and headed beyond the crossbar.

Faint hopes of the improbable we extinguished when Koscielny pushed Lewandowski to the floor 10 yards from goal and the additional assistant official advised Anastasios Sidiropoulos to upgrade his initial yellow card to a red.

The Poland international kept his calm to drill home the spot kick, sending David Ospina the wrong way, and he almost had a second on the end of a slick one-two with Vidal – Bayern turning on the style in front of their buoyant travelling support.

Robben gave them the lead on the night, intercepting a poor Ospina clearance and capitalising on the resulting disarray to slot into the corner.

Lewandowski then hit the post and the leggy 10-man hosts did not welcome a fresh Costa coming on to gallop towards goal from the right and make it three in the 78th minute.

Vidal's classily chipped fourth as the Arsenal defence crumbled terribly demonstrated the swagger of a side still chasing glory in three competitions and the Chile international had the brace his compatriot Sanchez might have hoped for five minutes from time, accepting Costa's pass with Ospina once again horribly exposed.