David Moyes saw his depleted Everton side spectacularly dismantled in the space of five second-half minutes at the Estadio da Luz as they went down to a 5-0 defeat to Benfica.
Any hopes of a recovery in this Europa League match - after Javier Saviola had opened the scoring - vanished as Oscar Cardozo scored twice and Luisao added to the gains to put Benfica on the road to an emphatic victory.
Saviola added a fifth goal - and despite the absence of 11 players, Everton boss Moyes must have been left bewildered at the way the Toffees caved in.
In the process, Everton suffered their first defeat in Group I and their first in eight games in all competitions.
Marco Andreolli struck a 94th-minute equaliser to earn Roma a 1-1 draw in their Group E clash with Fulham.
Fulham appeared to have completed a deserved victory after Mark Schwarzer saved a penalty, awarded when John Arne Riise went tumbling beneath Stephen Kelly's challenge.
Referee Paul Allaerts initially sent off the wrong player, brandishing the red card at Brede Hangeland, before being surrounded by a crowd of angry home players.
The official eventually relented, dismissing Kelly instead, and Fulham thought they had escaped when Jeremy Menez was denied by a brilliant save from Schwarzer.
But Andreolli stole in unmarked at the far post and lashed home from six yards out with virtually the last kick.
Hangeland had earlier struck his second goal for the club when he headed home a corner by Bjorn Helge Riise, though Fulham's superiority deserved at least another goal and they should have finished winners.
Celtic suffered their third European home defeat under Tony Mowbray as they lost 1-0 to Hamburg at Parkhead to leave them staring at an early exit from the competition.
Marcus Berg finished clinically in the 63rd minute after Ze Roberto had split open the Celtic defence as the German side joined Arsenal and Dinamo Moscow in further undermining Celtic's previously formidable home record.
The Bhoys, who have won just two of eight home games in all competitions under Mowbray, were sloppy in possession, although they created several first-half chances.
Only Barcelona had beaten Celtic in a European match at Parkhead in eight years before Mowbray took charge, but the latest defeat leaves the Hoops well adrift at the bottom of their group with just one point from three games.