Everton sank to their first UEFA Europa League defeat of the campaign with a 5-0 loss at Benfica on Thursday, while Lazio beat Villarreal 2-1 and defending champions Shakhtar Donetsk defeated Toulouse 4-0.
Everton went into the match at the Estadio da Luz missing 11 players through injury and debutant left-back Seamus Coleman was exposed for Benfica's opener. The 21-year-old got caught underneath the ball when Angel di Maria crossed from the left, allowing Argentinian striker Javier Saviola to volley home.
The English Premier League club's hopes of a comeback were extinguished within seven minutes of the second half, with Paraguayan international Oscar Cardozo scoring twice from close range after pinpoint left-wing assists from Saviola and then Di Maria.
Brazil centre-back Luisao added a fourth with a 52nd-minute header before Saviola touched home his second late on from another Di Maria assist as the hosts drew level with their opponents on six points at the Group I summit. In the group's other match, Belarussian side BATE Borisov won 2-1 at home to nine-man AEK Athens.
Argentinian starlet Mauro Zarate gave Lazio the lead in their Group G home game with Villarreal before Sebastian Eguren equalised five minutes before the break. Midfielder Matuzalem was sent off for the hosts mid-way through the second period but they snatched victory in injury time through captain Tommaso Rocchi.
The Rome outfit remain six points behind section leaders, Austrian champions Red Bull Salzburg, who beat Bulgaria's Levski Sofia 1-0 to secure a third straight victory.
Shakhtar, who won last season's tournament when it was still known as the UEFA Cup, were already 3-0 up at half-time against French side Toulouse as they maintained their perfect start in Group J.
Dutch league leaders Twente went down 2-0 at Moldovan outsiders Sheriff Tiraspol, while there were also wins for Athletic Bilbao, PSV Eindhoven, Fenerbahce, Club Brugge and Sparta Prague.
The top two teams from each of the 12 groups qualify for a place in the knockout round alongside the eight third-placed teams from the UEFA Champions League group stage.
Matches involving Groups A through F began later on Thursday. In Group A, Dinamo Zagreb were able to pull back a late goal, but nonetheless fell to Ajax 2-1, as Timisoara and Anderlecht played out a goalless draw.
Lille cruised to a decisive 3-0 victory over Group B opponents Genoa, as Valencia and Slavia Prague drew 1-1. In Group C, Hapoel Tel Aviv defeated Rapid Vienna 5-1 and a second-half goal for Hamburg was enough to dampen Celtic's night.
Heerenveen slipped past Hertha 1-0 in Group D and Sporting Lisbon emerged victorious, as Ventspils could not add to their second-half penalty and fell 2-1. Mario Andeolli's last-gasp strike earned Roma a share of the spoils after Brede Hangeland had given Fulham an early lead. In Group E's other match, Alexander Frei scored a brace to propel Basel past Sofia.
A second-half penalty for Panathinaikos was enough to see off Sturm Graz, while Galatasaray stormed to a 4-1 victory over Dinamo Bucuresti in Group F action.