Juventus dropped their first points of the Europa League campaign after coming from behind to draw 2-2 with visitors Rennes on Thursday.
Zeki Celik gave Juventus a fifth-minute lead, but the French side kept their composure and were level 10 minutes later when Jordan international Musa Al-Taamari finished from close range for his first goal in the competition.
Rennes then stunned the hosts with a Boulaye Dia penalty two minutes before the break as the Italians struggled to create chances until Nick Woltemade equalised from the spot in the 67th minute.
The German forward twice went close to scoring again as Luciano Spalletti's team upped the pressure, and Juve thought they had won it in the 88th minute when Jhon Lucumi found the net from close range, but his effort was ruled out for offside.
The draw at least spared Juventus a second successive defeat following Sunday's 3-0 home loss to Lazio in Serie A.
Jonas Hofmann made the most of his surprise start for Bayer Leverkusen, scoring twice in three minutes to give the Bundesliga side a 2-0 victory at OFI Crete to go top of the table with their third straight win.
OFI, who stunned Hoffenheim 2-0 in their opening league-phase match, were twice caught napping by Hofmann, who was added to the side following an injury to Martin Terrier.
Leverkusen have nine points and lead Ferencvaros on goal difference after the Hungarian side beat Torreense 4-1.
Sunderland, who were also chasing a third win, took a second-minute lead against Lech Poznan through Timur Tutierov but Leo Bengtsson grabbed a 70th-minute equaliser to earn the Polish side a 1-1 draw. Sunderland have seven points, level with fourth-placed Juventus.