Arsenal got through despite an embarrassing 2-1 home defeat by Ostersund.

Borussia Dortmund snatched a late goal at Atalanta to progress with a 1-1 draw, while Milan with three-goal leads from the away legs, completed the formality of qualifying with a 1-0 win at home on Thursday.

The evening was marred by the death of a policeman in Bilbao after rivals fans fought in the streets before the match between local side Athletic and Spartak Moscow, won 2-1 by the Russian team who still went out 4-3 on aggregate.

Arsenal had a three-goal lead from last week's win in Sweden but were rattled when Hosam Aiesh and Ken Sema scored twice in two minutes for Ostersund midway through the first half.

The North London side were spared further humiliation, though, after Ronald Mukiibi miscued when trying to clear a cross and defender Sead Kolasinac thumped the ball into the net from close range two minutes into the second half.

Atalanta scored against Dortmund when Rafael Toloi prodded the ball home at the far post after Mattia Caldara flicked on a corner in the 11th minute to make it 3-3 on aggregate.

There were then chances at both ends until Dortmund's Marcel Schmelzer snapped up the rebound, after Etrit Berisha failed to hold a Marco Reus shot, to put the Bundesliga side through.

Sporting, Viktoria Plzen, Olympique Marseille and Salzburg also qualified and will go into the hat for the last 16 draw which will be made on Friday.