
Red Star lost 2-1 at Estonian champions Levadia Tallinn, with the 37th-minute strike from Igor Burzanovic their key moment. Red Star advanced from aggregate 2-2 score in the second round tie, having won the first leg in Serbia 1-0.
Levadia scored from Deniss Malov in the 34th and Konstantin Nahk in the 68th, but the hosts then failed to create a major upset in the final 22 minutes of play.
Red Star now run into Rangers in the deciding tie for a place in the lucrative group stage, set for August 14/15 and 28/29. Red Star beat the Scots in the second round en route to the title in 1991.
Rangers got their place in the third qualifying round on Tuesday with a 1-0 win at Macedonian champions Zeta Golubovci for a 3-0 aggregate scoreline.
Zeta face further trouble as the ruling body UEFA announced Wednesday an investigation into alleged racist abuse by their fans towards Rangers players Jean Claude Darcheville and DaMarcus Beasley.
Red Star were not the only ex-champion in action on Wednesday.
The 1986 winners Steaua Bucharest beat Poland's Zaglebie Lubin 2-1 on the night and 3-1 overall, but were not fully assured of advancing until Dorel Zaharia scored with eight minutes left. Steaua now run into Belarussian champions Bate Borisov.
Abdou Razack Traore scored a hat-trick as Norway's Rosenborg got the biggest victory of the second entire qualifying round, 7-1 on the night and 10-1 overall against Kazakh minnows Astana. The Trondheim club are also favoured in the next round against Finland's Tampere.
Shakhtar Donetsk completed a 4-1 aggregate win over Armenia's Pyunik with a 2-1 score on the night.
But in order to make the group stage the second straight year, they need to overcome Giovanni Trappatoni's Red Bull Salzburg, the Austrians routing Latvia's Ventspils 4-0 for a 7-0 triumph.
The other Ukrainian heavyweights, Dynamo Kiev, saw their opponent determined, with Bosnia's Sarajevo stunning RK Genk on away goals despite a 1-0 home defeat, having prevailed 2-1 in Belgium last week.
Turkey's Besiktas was among other clubs to advance, 3-0 Wednesday and 4-0 from both legs against Sheriff Tiraspol of Moldova.
DPA