Atletico Madrid completed the formalities of their Europa League last-32 tie with FC Copenhagen, winning 5-1 on aggregate as Kevin Gameiro scored in a 1-0 victory in the second leg.
The favourites to win Europe's second-tier competition were never in real doubt of their progression, and went five goals to the good on aggregate when Gameiro struck a stunner after seven minutes.
Diego Simeone left Antoine Griezmann on the bench with the tie as good as won, and his side could have had a second on the night but Gameiro was denied again.
Serie A leaders Napoli gave Leipzig a serious fright in Germany, but a 2-0 win was in vain as last week's 3-1 loss proved too much to come back from.
Visiting coach Maurizio Sarri, who was given his own smoking room by Leipzig, named a strong team, and Piotr Zielinski's first-half goal gave Napoli hope.
The fightback looked as though it would not materialise, but Lorenzo Insigne's strike with four minutes to play set up a tense finale.
Borussia Dortmund needed an 83rd-minute goal from Marcel Schmelzer to ensure they did not go out on away goals to Atalanta.
Having scored twice in a 3-2 loss in Germany, Atalanta had hoped Rafael Toloi's early strike would be enough only for Schmelzer to save Dortmund late on.
Athletic Bilbao's encounter with Spartak Moscow was overshadowed by violent scenes away from the ground as fans clashed.
Bilbao were beaten 2-1 on the night but their 3-1 success in Russia was enough to see them go through.
Zenit overturned Celtic's slender first-leg lead to go through 3-1 on aggregate, with former Chelsea defender Branislav Ivanovic scoring one and making another.
AC Milan went through to the last 16 after beating Ludogorets 1-0 thanks to a Fabio Borini goal, sending them into the next round on a 4-0 aggregate score.
Lazio, who sit in the fourth and final Champions League spot in Serie A, thrashed FCSB 5-1 with Ciro Immobile scoring a hat-trick to brush off the surprise 1-0 first-leg defeat in Romania.
Nice were made to pay for their first-leg collapse as a 1-0 defeat at Lokomotiv Moscow saw the Russian side through 4-2 on aggregate.
Lokomotiv had come back from two goals down to win the opening game in France, and Igor Denisov grabbed the only goal of the return match in the 30th minute.
Last season's semi-finalists Lyon won 1-0 at Villarreal to go through 4-1 on aggregate, while Sporting Lisbon and Viktoria Plzen also reached the last 16.
RB Salzburg's 2-1 victory over Real Sociedad was enough for them to continue in the competition and though Marseille lost 1-0 to Braga, they marched on nevertheless having held a 3-0 lead from the first meeting.