ZURICH (REUTERS) - Schalke hit back from two goals down to draw 2-2 and overcome fellow German Bundesliga side Borussia Monchengladbach on away goals in their Europa League last-16 tie.
Lyon clung on to eliminate Roma 5-4 on aggregate despite a 2-1 defeat, while Ajax and Anderlecht also went through along with Genk.
Russia's interest in this season's Europa League ended as Krasnodar threw away a promising position at home to Celta and lost 2-0 for a 4-1 aggregate defeat.
Besiktas hammered Olympiakos 4-1 (5-2 on aggregate) despite having Vincent Aboubakar, their opening scorer, sent off six minutes before half-time.
Schalke, trailing at half-time to a deflected shot from Andreas Christensen and a long range rocket from Mahmoud Dahoud, were helped by a bumpy pitch as they hit back against Monchengladbach.
Leon Goretzka's low shot appeared to be going straight to Monchengladbach goalkeeper Yann Sommer but hit a divot and looped over the Swiss international and into the net in the 54th minute.
"It's tough, I can't say anything other than that," said Sommer. Dahoub then turned villain as his handball led to a Schalke penalty converted by Nabil Bentaleb in the 68th minute to give Schalke an away goals win after a 3-3 aggregate draw.
Lyon took a 4-2 lead to Roma's Stadio Olimpico and quickly added to it when Mactour Diakhaby was allowed a free header from six metres in the 16th minute. Kevin Strootman levelled within a minute, turning in Daniele De Rossi's free-kick at the back post, and it was one-way traffic after that as the home side poured forward.
Lyon's Lucas Tousart turned Stephan El Shaarawy's cross into his own net to put Roma 2-1 ahead on the hour and the hosts thought they had done enough to progress with an Edin Dzeko effort but the Bosnian forward was ruled offside.
First-half goals from Bertrand Traore and Kasper Dolberg gave Ajax a 2-0 win over FC Copenhagen which took the four-time European champions through, 3-2 on aggregate.
Frank Acheampong's second half goal was enough for Belgian side Anderlecht to beat APOEL 1-0 and go through 2-0 on aggregate.
Genk coasted through 6-3 on aggregate against fellow Belgians Gent after a 1-1 draw.
Besiktas, who drew 1-1 at Olympiakos last week, got off to a flying start as Aboubakar and Ryan Babel scored inside the first 22 minutes.
The Greek side pulled one back with Tarik Elyounoussi's acrobatic volley in the 31st minute and were given more hope when Aboubakar was dismissed for violent conduct eight minutes later.
But Olympiakos left themselves too open and further late goals from Babel and Cenk Tosun saw the Turks ease through.
The draw for the quarter-finals will be held on Friday.