Rosenborg's hopes of qualification took a blow after a shock 2-1 home defeat to Sligo Rovers in the UEFA Europa League on Thursday.
The 22-time champions of Norway had home advantage in the second-round qualifying tie at the Lerkendal Stadion.
However, they will travel to Ireland needing to overturn the one-goal deficit, as second-half goals from Alan Keane and Danny North put the visitors in control.
Mikkel Diskerud offered hope of a late comeback when he struck nine minutes from time, but it proved in vain as Sligo held on for a precious win.
Koper were also 2-1 victors on their visit to Neftci, while the likes of Botev Plovdiv, Mlada Boleslav, Split and Zulte Waregem still have to work to do after winning by the same scoreline at home.
IFK Gothenburg have won Europe's secondary club competition on two occasions in 1982 and 1987, and the Swedish outfit look destined for the next round after a 3-0 win at Gyori ETO.
Lasse Vibe got the visitors off to a flying start in the eighth minute and Jakob Johansson and May Mahlangu added furth goals in the second half.
Fellow Swedish sides Brommapojkarna and Elfsborg had differing fortunes. The former routed Crusaders 4-0, while the latter were beaten 1-0 at home by Inter Baku.
Russian Premier League outfit Krasnodar are virtually assured a spot in the third round of qualifying thanks for a 4-0 win at Sillamae Kalev.
Ari, Yury Gazinskiy, Wanderson and Vladimir Bystrov were all on the scoresheet in the comfortable win.
Grodig too won 4-0 on their travels at Cukaricki, and Trencin secured the same score at home to Vojvodina. Molde put one foot in the next round thanks to a 4-1 home success over Gorica.
Kazakh outfit Astana should progress after a 3-0 home win over Hapoel Tel Aviv, while Belarus side Dinamo Minsk beat MYPA by the same score. Zorya won 3-0 on their visit to Laci.
The matches between Kairat and Esbjerg, RoPS and Asteras Tripolis, CSKA Sofia and Zimbru, Luzern and St. Johnstone and Neman Grodno and FH are all nicely poised after finishing 1-1.
Shakhter Karagandy, Spartak Trnava and Tromso played out stalemates on their visits to Atlantas, Zestafoni and Vikingur, while Jagodina took a valuable 0-0 draw away from CFR Cluj.
There were no goals in the matches involving Bursaspor and Chikhura Sheva, Aberdeen and Groningen, or Metalurg Skopje and Zeljeznicar.
Omonia Nicosia and Diosgyor take 2-0 leads back to their respective home legs with Buducnost and Lovech. Petrolul Ploiesti scored twice in the last 13 minutes to win 2-0 at home to Flamurtari Vlore.
Dundalk face a tricky task after losing 2-0 at home to Hajduk Split, while Motherwell surrendered a two-goal lead in a 2-2 draw at home to Stjarnan.
One goal was all that was needed for Slovan Liberec to win on their visit at Kosice, while Nomme Kalju were 1-0 victors at home to Lech Poznan. Ruch Chorzow also have a one-goal cushion ahead of the second leg following an entertaining 3-2 triumph over Vaduz.
Linfield and Rijeka triumphed 1-0 in their home ties, as did Shakhtyor and Haugesund on their visits to Derry City and Sarajevo.
|Mancini demands killer instinct from Inter after Carpi scare|
|Allegri praises Juve spirit in poor display at Roma|
|Monaco 0 Paris Saint-Germain 3: Cavani up and running as PSG march on|
|Carpi 1 Inter 2: Jovetic double settles lacklustre encounter|
|Sevilla 0 Atletico Madrid 3: Hosts thwarted once again by Simeone|
|Inter land Wolfsburg´s Perisic|
|Shelvey and Vardy named in England squad|
|Montero injury nothing serious - Monk|
|Van Gaal in the dark over De Gea future|
|Werder Bremen 2 Borussia Monchengladbach 1: Vestergaard seals first win|
|Roma 2 Juventus 1: Pjanic and Dzeko down stuttering champions|
|United could not cope with Swansea - Van Gaal|
|Monk: Swansea are a Premier League force|
|Lyon swoop for Malaga midfielder Darder|
|Tuchel hails table toppers Dortmund|
|No complaints for Neil after Southampton loss|
|Swansea City 2 Manchester United 1: Gomis spoils Van Gaal´s day|
|De Bruyne relieved to complete City switch|
|Koeman stands firm over Mane and Wanyama futures|
|Bahebeck rushed to hospital with chest pains|
|Borussia Dortmund 3 Hertha Berlin 1: Tuchel maintains perfect start|
|Manchester City complete De Bruyne swoop|
|Weihrauch strikes twice as Bayern overpower fans|
|Saint-Etienne 2 Bastia 1: Two sent off in first defeat of the season for visitors|
|Southampton 3 Norwich City 0: Tadic at the double for Koeman´s men|
|Paderborn swoop for Kirch|
|Bayern loan Coman from Juventus|
|Schalke will not rush decision over Wolfsburg target Draxler|
|Fenerbahce secure Markovic loan|
|O´Neill trims Ireland squad to 28|
|Sherwood: I´ve done my hamstring|
|Dante set for Wolfsburg switch|
|Neymar knows nothing of Man United interest|
|Ibisevic leaves Stuttgart for Hertha|
|International break unwelcome for Mourinho|
|Muto a ´perfect fit´ for Mainz|
|Lampard pledges NYC commitment|
|Van Gaal: I listen to Rooney|
|MLS Review: Whitecaps falter, Eastern Conference heats up|
|´I think a yellow would have been harsh´ - Noble baffled by his red card|
|Rodriguez´s quality ´unquestionable´ - Benitez|
|Abdennour chooses Valencia|
|Giovinco to fly to Italy despite injury|
|La Liga Review: Real Madrid, Celta notch big wins|
|Mihajlovic: I feel like I lost|
|Real Madrid 5 Real Betis 0: Rodriguez scores twice in Benitez´s first Bernabeu win|
|Balotelli has a lot of work to do, declares Bacca|
|Luis Enrique delighted with Vermaelen´s form|
|Bundesliga Review: Leverkusen no match for Muller-inspired Bayern, Frankfurt thump Stuttgart|
|Milan 2 Empoli 1: Adriano header seals first league win for Mihajlovic|
|Ligue 1 Review: Fekir hat-trick inspires Lyon, Reims take Lorient apart|
|Barcelona 1 Malaga 0: Vermaelen rewards patient champions|
|Muller denies Van Gaal contact|
|Pochettino not concerned about goalless Kane|
|Martinez hails ´immense´ Stones|
|Flores not concerned by lack of Watford goals|
|Evans completes West Brom switch|
|Howe remains upbeat despite concerning injuries|
|Rash Cattermole frustrating Advocaat|
|Bayern Munich 3 Bayer Leverkusen 0: Muller marks 200th appearance in style|
|Tottenham 0 Everton 0: Howard keeps hosts at bay|
|Sako gives Palace new dimension - Pardew|
|Rodgers rues self-inflicted Liverpool defeat|
|Villa were robbed during Sunderland draw, blasts Sherwood|
|Football League Review: Brighton move top, Orient maintain winning start|
|I wish I had a fourth substitute, says Chelsea boss Mourinho|
|Pulis hails West Brom match-winner Rondon|
|´Gladiator´ spirit is more important than anything - Ranieri|
|Bilic defends ´park the bus´ tactics after Anfield win|
|Pellegrini quiet on De Bruyne after record-breaking win|
|Hughes fumes at Stoke dismissals after West Brom loss|
|Mourinho: Chelsea did not deserve Palace defeat|
|Scottish Premiership Review: Celtic return to the summit as Hearts suffer surprise defeat|
|Liverpool 0 West Ham 3: Defensive woes return for Rodgers´ men|
|Manchester City 2 Watford 0: Sterling opens account as City become record breakers|
|Bournemouth 1 Leicester City 1: Vardy rescues a point|
|Chelsea 1 Crystal Palace 2: Late Ward winner seals dramatic victory|
|Stoke City 0 West Brom 1: Rondon gives Pulis win over nine-man hosts|
|Aston Villa 2 Sunderland 2: M´Vila and Lens secure hard-fought point|
|Blackett moves to Celtic on loan|
|McClaren laments ´harsh´ Mitrovic red|
|Wenger: Arsenal ´cautious´ in Newcastle win|
|Sevilla can mirror Atletico strengths - Simeone|
|Ibrahimovic and Di Maria in PSG squad for Monaco clash|
|Newcastle United 0 Arsenal 1: Mitrovic off as Coloccini own goal settles it|
|Barca´s Suarez ends Sevilla loan to make Villarreal switch|
|Allegri confirms imminent Coman departure|
|Garcia demands more ahead of Juve clash|
|Knee injury sidelines Ozil|
|Dortmund boost defence with Mainz´s Park|
|Ruddy hoping to impress Hodgson|
|Wolfsburg proved there is life after De Bruyne - Hecking|
|Van Gaal unsure if Romero will replace De Gea long-term|
|Dzeko wants Totti partnership at Roma|
|No excuses for City - Pellegrini|
|San Jose Earthquakes 1 LA Galaxy 0: Salinas´ header levels Cali Clasico tally|
|Koeman plays down expectations|
|Stuttgart´s Langerak suffers surgery setback|
|Rodgers hails Milner´s leadership, mentality|
|Conte hints at Giovinco recall, doesn´t rule out Balotelli|
|Martinez slams Chelsea over Stones pursuit|
|Leverkusen are title contenders - Guardiola|
|Babel in sexism controversy|
|Pellegrini prepared to wait for Otamendi|
|Sevilla v Atletico Madrid: Llorente hoping to repay faith|
|Veloso back for Portugal|