Schalke, Shakhtar Donetsk and Zenit, all of whom still have perfect records, joined Ajax in sealing early qualification while Aritz Aduriz scored all of Athletic Club's goals in a 5-3 win.
Article top media content
Ajax, Schalke, Shakhtar Donetsk and Zenit became the first teams to qualify for the UEFA Europa League round of 32 on a goal-filled night that yielded a competition record five in one game for Athletic Club's Aritz Aduriz.
Matchday four results (click for video highlights, line-ups, stats and more)
Ajax 3-2 Celta Vigo
Anderlecht 6-1 Mainz
APOEL 1-0 Young Boys
Astana 1-1 Olympiacos
Astra Giurgiu 1-1 Viktoria Plzeň
Athletic Club 5-3 Genk
Austria Wien 2-4 Roma
Braga 3-1 Konyaspor
Fenerbahçe 2-1 Manchester United
Fiorentina 3-0 Slovan Liberec
Gabala 1-2 St-Étienne
Gent 3-5 Shakhtar Donetsk
Maccabi Tel-Aviv 0-0 AZ Alkmaar
Nice 0-2 Salzburg
PAOK 0-1 Qarabağ
Panathinaikos 0-3 Standard Liège
Sassuolo 2-2 Rapid Wien
Schalke 2-0 Krasnodar
Sparta Praha 2-0 Hapoel Beer-Sheva
Southampton 2-1 Internazionale Milano
Villarreal 1-2 Osmanlıspor
Zenit 2-1 Dundalk
Zorya Luhansk 1-1 Feyenoord
Zürich 0-0 Steaua Bucureşti
Thursday's 24 fixtures produced 77 goals, four shy of the high watermark for a single matchday, set in 2010/11.
Schalke, Shakhtar and Zenit have all won their respective sections after maintaining their 100% records. The fourth qualified side, Ajax – 3-2 victors at home to Celta Vigo – require a point against Panathinaikos in three weeks' time to lock down top spot in Group G.
Giuliano took his tally to five with a strike in each half as Mircea Lucescu's Zenit defeated Dundalk 2-1 at a snowy Stadion Petrovskiy in Group D.
The former Dnipro Dnipropetrovsk playmaker is level at the head of the 2016/17 scorers' chart with Aduriz, who registered all of Athletic's goals, three of them penalties, in a 5-3 triumph over Genk.
Shakhtar conceded inside 20 seconds away to Gent but recovered to post a 5-3 win of their own that gives them an unassailable lead in Group H. Similarly, Schalke cannot be overhauled in Group I after a 2-0 success against Krasnodar.
Elsewhere, Moussa Sow contributed a goal of the season contender as Fenerbahçe edged out Manchester United 2-1, beating David de Gea with a stunning bicycle kick.
Jeremain Lens doubled the Istanbul club's advantage when he curled in a free-kick. Wayne Rooney responded with a fine effort from outside the area, one that drew him level with Ruud van Nistelrooy as the Old Trafford team's record 38-goal marksman in UEFA club competition.