Manchester United earned their first Europa League win with a 2-0 victory over PAOK, Tottenham Hotspur's perfect start ended with a 3-2 loss at Galatasaray and Lazio top the standings after a 2-1 victory over Porto on Thursday.
A brace from Amad Diallo gave United their first success in this season's competition, coming under interim manager Ruud van Nistelrooy after they had drawn the previous three games with Erik ten Hag was in charge.
Amad's first came five minutes after the break when he met a Bruno Fernandes cross with a looping header which found the far corner, and he added a solo second 13 minutes from time.
United have six points in the standings, three behind Spurs who despite going down to 10 men almost made a dramatic comeback in Istanbul where Victor Osimhen scored twice for the hosts and Will Lankshear grabbed his first goal for Spurs before being sent off.
Ajax strolled to a 5-0 win over Maccabi Tel Aviv, Athletic Bilbao came from behind to beat Ludogorets 2-1 and Anderlecht were denied joining Lazio on top as a late own goal left them with a draw in Latvia at RFS.
Yunus Akgun gave Galatasaray an early lead with a stunning half-volley but Spurs levelled when Brennan Johnson's layoff across the goal left Lankshear with a simple tap-in.
Radu Dragusin was caught napping at the back in the 31st minute and was dispossessed by Mauro Icardi. The ball fell to Dries Mertens who slipped a pass to Osimhen and the Nigerian striker found the bottom corner.
Osimhen struck again six minutes from the break and Lankshear received his second booking on the hour mark, but 10-man Tottenham pulled a goal back when substitute Dominic Solanke back-heeled Pedro Porro's cross into the net.
Lazio top
Lazio made it four wins from four to take control at the top of the standings thanks to an added-time goal from Pedro.
The Italian side went ahead at the end of the first half through Alessio Romagnoli's header but Porto drew level through Stephen Eustaquio.
It looked like Lazio would have to settle for a draw but with time running out Pedro turned a cross from Gustav Isaksen into the net.
Anderlecht could have joined them on 12 points, with Mario Stroeykens putting them ahead five minutes from time but RFS snatched a draw deep into added time when Moussa N'diaye put the ball into his own net.
Bilbao moved on to 10 points with their comeback win in Bulgaria against Ludogorets after Inaki Williams and Nicolas Serrano scored second-half goals in quick succession.
Ajax are also on 10 after cruising to victory over Maccabi with goals from Bertrand Traore, Kenneth Taylor, Mika Godts, Brian Brobbey and Kian Fitz-Jim.
Eintracht Frankfurt overcame Slavia Prague 1-0 thanks to Omar Marmoush's goal direct from a free kick and they remain two points behind Lazio.
AS Roma were held to a 1-1 draw at Union Saint-Gilloise where Gianluca Mancini put the Italians ahead before Kevin MacAllister equalised for the Belgian side, which leaves the Italians down in 20th on five points.