Lukas Julis scored a hat-trick as Sparta Prague claimed a stunning 4-1 away win that sent Celtic to the bottom of their Europa League group.
The Czech Republic side had a clutch of players missing through injury and Covid-19 issues, including number one goalkeeper Milan Heca and teenage star Adam Hlozek, but they took the lead in the 26th minute through striker Julis, and he scored a second just before the interval.
Celtic substitute Leigh Griffiths pulled a goal back in the 64th minute, shortly after coming off the bench, and the Scottish champions, who had lost to AC Milan at home and drawn at Lille in their first two Group H fixtures, then piled on the pressure.
However, they were undone yet again in the 76th minute when Moberg Karlsson skipped past Republic of Ireland defender Shane Duffy with ease and set up Julis to tap in.
Substitute Ladislav Krejci headed in a fourth in the final minute to complete a chastening night for Neil Lennon's side.
Arsenal came from behind to maintain their 100 per cent start to their Europa League campaign as two own goals helped them see off Molde.
The Gunners had already beaten Rapid Vienna and Dundalk in Group B and continued on their way to the knockout stages with a solid if unspectacular 4-1 victory at Emirates Stadium.
Martin Ellingsen's long-range effort gave the reigning Eliteserien champions a shock lead against a slow-starting Arsenal side which showed nine changes from the weekend win at Manchester United.
But own goals from Kristoffer Haugen and Sheriff Sinyan either side of half-time turned the tide, with Nicolas Pepe and Joe Willock wrapping up the win with fine finishes.
Earlier, Rapid Vienna saw off Dundalk 4-3 in the dramatic other game in Group B.
Kelechi Iheanacho's brace kept dominant Leicester on course to reach the Europa League knock-out stages after a crushing 4-0 win over Braga.
The striker’s double helped the Foxes take control of Group G and they sit top, three points clear of Braga, after a third straight win in Europe.
Iheanacho has now scored three times in the campaign as he deputised for Jamie Vardy, with Brendan Rodgers having the luxury of resting his eight-goal top scorer.
Abel Ruiz missed a fine chance to give Braga a lifeline before Dennis Praet and James Maddison wrapped up victory for the Foxes’ biggest European win.
Carlos Carvalhal’s side, expected to be Leicester’s main challengers for top spot, were simply brushed aside and halfway through the stage the Foxes are in pole position to win the group.
Harry Kane scored his 200th goal for Tottenham in a 3-1 Europa League win against Ludogorets.
The 27-year-old joined Jimmy Greaves and Bobby Smith in Spurs' 200 club following his first-half header in Bulgaria.
Kane produced his 10th assist of the campaign when teeing up Lucas Moura for Tottenham's second.
Claudiu Keseru threatened to make it another uncomfortable evening for Spurs, but Giovani Lo Celso's goal just after the hour made the game safe.
The win helps Tottenham get a grip back on Group J and, with the reverse game against Ludogorets - the weakest team in the group - up next, they should have no problems progressing.
Alfredo Morelos wrote his name into the Rangers record books but his 22nd European goal was not enough to daze 10-man Benfica after a 3-3 draw at the Estadio da Luz.
The Colombian was celebrating as he put Steven Gerrard's team 3-1 up in Lisbon, moving him past the club benchmark previously set by Ibrox great Ally McCoist.
But the visitors switched off in the final 13 minutes and paid the price as Rafa Silva netted before substitute Darwin Nunez fired home an injury-time equaliser.
The Scots fell behind just 60 seconds in when Connor Goldson put through his own net, but the game looked to have turned dramatically in their favour when former Manchester City defender Nicolas Otamendi was sent off for a professional foul.
Gerrard watched with delight as his team grabbed a quick-fire double thanks to Diogo Goncalves’s own goal and a Glen Kamara strike, with Morelos adding his record-breaking third just after the break.
Despite letting slip a win which would have been Benfica’s first ever Europa League defeat at home, the Light Blues remain well placed to reach the last 16, sitting level with the Portuguese giants at the top of Group D on seven points.
Elsewhere in Group D, Lech Poznan secured a 3-1 win over Standard Liege.
In Group A, former Manchester United and Arsenal attacker Henrikh Mkhitaryan opened the scoring with less than a minute on the clock as Roma put five past CFR Cluj.
Bayer Leverkusen and Slavia Prague secured 4-2 and 3-2 victories respectively against Hapoel Be'er Sheva and Nice in Group C.
Andrija Zivkovic scored a brace as PAOK came from behind to secure a 4-1 win over PSV in Group E.
Napoli joined AZ Alkmaar on six points at the summit of Group F following a 2-1 win at Rijeka, while the Dutch side went down 1-0 away to Real Sociedad. The Spanish team also have six points from their opening three fixtures.
Elsewhere, Sivasspor ran out comfortable 2-0 winners against Qarabag in Group I.