The Norwegian side produced a superb performance in the first leg to all but secure progress, midifielder Magnus Andersen hitting a brace in a dominant win.
Rosenborg continued the theme of emphatic Norwegian success, Alexander Soderlund scoring twice, including one from the spot, in a 4-0 victory against Jelgava of Latvia.
Botev Plovdiv were also 4-0 winners over San Marino's Libertas, and Gilman Lika's injury-time strike gave Flamurtari Vlore a 3-2 triumph at Sioni.
Tiraspol's late comeback fell short as the Moldovans lost 3-2 at home to Inter Baku, whose Azerbaijani rivals Qabala face an uphill battle in their away leg after a 2-0 reverse to Siroki Brijeg.
Slovenian side Koper took a commanding lead in their tie with 10-man Celik, Miroslav Covilo's double helping them to a 5-0 triumph.
There was treble joy for Kazakhstan on Thursday, Astana winning 4-1 at Pyunik, Shakhter Karagandy beating Shirak 2-1 and Kairat earning a slender 1-0 success over Kukesi.
It was a good night for Northern Irish sides as attacker Michael Carvill's 88th minute strike gave Linfield a 2-1 win at B36 in the Faroe Islands.
Crusaders backed up that result by beating Ekranas of Lithuania 3-1, and Derry City were 4-0 winners in an all-British affair with Aberystwyth Town, who had goalkeeper Mike Lewis sent off after 23 minutes.
Airbus UK Broughton fared better in a 1-1 draw with Haugesund of Norway, however, Bangor City were thrashed 4-0 by Iceland's Stjarnan.
Finnish outfit VPS emerged as 2-1 winners in all-Scandinavian clash with Brommapojkarna of Sweden, while their league rivals MYPA beat IF of the Faroe Islands 1-0 thanks to Denis Abdulahi's strike.
Erik Sabo's brace proved key as Spartak Trnava won 4-2 at Hibernians.
Slovenians Rudar drew 1-1 with Laci of Albania, but Andorra's Sant Julia have a mountain to climb if they are to qualify after losing 4-0 in Serbia to Cukaricki.
Vikingur were the only Faroe side to experience triumph, Andreas Olsen scoring the winner in a 2-1 defeat of Latvia's Daugava Daugavpils.
Elsewhere, there were goalless draws in the games between Veris and Litex Lovech, Banga and Sligo Rovers and Lovcen's trip to Zeljeznicar.
