Celtic dramatically crashed out of the Champions League for the second time this season with a 1-0 playoff defeat by Maribor at Parkhead taking the visitors through 2-1 on aggregate.
The Hoops were beaten 6-1 on aggregate by Legia Warsaw in the third qualifier but were reinstated after the Polish club were effectively thrown out by UEFA for fielding a player who should have been suspended in the second leg at Murrayfield.
Confident following their 1-1 draw in Slovenia last week, the Scottish champions were booed off at half-time following 45 minutes of struggle.
The introduction of Kris Commons at the start of the second half for Beram Kayal saw a vast improvement but Maribor skipper Tavares grabbed the crucial goal in the 75th minute, costing the Parkhead club around 20 million pounds in revenue but much more in reputation as the spotlight falls on boss Ronny Deila.
Celtic will go into the draw for the Europa League but that will be scant consolation for the angry Hoops fans, who made their feelings known at the final whistle.
Goals from Yacine Brahimi and Jackson Martinez helped Porto dominate Lille with a 2-0 second-leg win at the Estadio do Dragao.
The intriguing tie was finely poised following the Portuguese club's narrow first-leg victory but back on home turf Julen Lopetegui's side were more confident and took the lead through summer signing Brahimi in the 49th minute.
Colombian hitman Martinez struck in the 75th minute to make it 3-0 on aggregate to the 2004 European champions.
Ten-man Zenit St. Petersburg cruised into the group stage, beating Standard Liege 3-0 in Russia after two goals by Hulk to seal a 4-0 aggregate win.
Ahead 1-0 from the first leg, Zenit opened the scoring through Jose Rondon's deflected header in the 30th minute but saw Russia's Viktor Fayzulin sent off before half-time.
Hulk extended their lead from the penalty spot in the 54th minute after Igor Smolnikov was tripped by Jelle Van Damme and the Brazil forward struck four minutes later, brushing off defenders before scoring. Liege's Ricardo Faty was sent off in the 89th minute.
Representing Cyprus in Friday's draw will be APOEL FC, who scored four goals past Aalborg without reply to progress 5-1 on aggregate.
Vinicius notched inside two minutes and further strikes from Tomas De Vincenti (43), Stathis Aloneftis (64) and Cillian Sheridan (75) fired the Nicosia outfit well clear of their Danish opponents.
Elsewhere, BATE Borisov were comfortable 4-1 aggregate winners over Slovan Bratislava.
Mikhail Gordeichuk (41) opened the scoring for the Belarusian champions and late goals from Sergey Krivets (84) and Vitali Rodionov (85) put Bratislava to bed.
Guinean striker Seydouba Soumah saw red for the Slovakian club 11 minutes from time.