Schalke scored three second-half goals to take a commanding lead in their Uefa Cup tie with 10-man Levski Sofia as the German side ran out 3-1 winners.
Lincoln (centre) was on the scoresheet for Schalke
Sofia had taken the lead on six minutes through Daniel Borimirov but saw Cedric Bardon dismissed on 35 minutes.
Schalke made use of their numerical advantage after the break with Gustavo Varela finding the net on 48 minutes.
Brazilian Lincoln put the visitors ahead before German international striker Gerald Asamoah sealed the win.
The tie between the two Bucharest teams is delicately poised after a 1-1 draw at Rapid.
More than 2,000 police were dispatched at the Lia Manoliu stadium to prevent fans' rivalries from turning violent in the first all-Romania match in European club competition.
The 1986 European Cup champions Steaua took just five minutes to open the scoring when winger Banel Nicolita stroked home Daniel Oprita's neat pass.
Rapid almost got a quick equaliser but Daniel Niculae's header hit the post seven minutes later.
But former Coventry striker Viorel Moldovan levelled on 50 minutes, tapping in a loose ball after Steaua goalkeeper Carlos Alberto Fernandes failed to hold a Emil Dica shot.
The winner of that tie will face the victor of Middlesbrough's tie with Basle, with the Swiss side taking a 2-0 lead into the second leg at the Riverside.
In the last of the quarter-final matches, Spanish side Sevilla trounced Zenit St Petersburg 4-1 thanks to a brace from Javier Saviola.
The Argentina striker gave Sevilla the lead on 15 minutes, but the Russians replied on the stroke of half time through Alexander Kerzhakov.
St Petersburg were then reduced to ten men when defender Erik Hagen hauled down former Tottenham striker striker Frederic Kanoute.
Jose Luis Marti dispatched the resulting penalty before Saviola completed his double 10 minutes from time.
Andrei Arshavin compounded the visitors' misery on 90 minutes when he too saw red and Claro Adriano Correia completed the rout with a late strike.