Juventus' players celebrate after their Europa League quarter-final win at Lyon. (AFP/Philippe Desmazes)
After losing their 14-match unbeaten run in a 2-0 loss at Napoli at the weekend, Juve continued to labour in France.
They were heading for a scoreless stalemate until Leonardo Bonucci broke the deadlock five minutes from time.
Andrea Pirlo's corner fell to Paul Pogba whose powerful close-range drive was blocked but Bonucci was on hand to blast the ball home past Anthony Lopes in the Lyon goal.
Moments earlier, an unmarked Mirko Vucinic had managed to fire over the crossbar from just six yards out in a crude snapshot of the lack of quality involved.
Lyon struggled to carve out a meaningful chance while Juventus's Argentine star Carlos Tevez had headed wide in the first half.
Tevez, who has 18 Serie A goals this season, remains without a goal in continental competition since scoring for Manchester United against Porto in the 2008/09 Champions League.
"It was tough as Lyon were trying to stop us from playing with man-marking all over the field," said Juventus coach Antonio Conte.
"I think the victory is a deserved result, but we know that we have achieved nothing yet, there is a second leg to play and a semi-final to achieve."
Portuguese giants Benfica and Porto both came out of their first legs with 1-0 wins.
Last season's runners-up Benfica, who put out Tottenham in the last-16, won at Alkmaar in the Netherlands thanks to a 48th-minute goal from Eduardo Salvio.
He was first to a rebound after Alkmaar's Costa Rican goalkeeper Esteban had saved from Oscar Cardozo.
Porto, the 2011 champions, edged Sevilla 1-0 with stand-in captain Eliaquim Mangala scoring on the half-hour.
Steven Defour and Ricardo Quaresma both saw efforts come off the post for Porto but they ended the game with 10-men after Fernando was red-carded.
Argentine playmaker Matias Delgado scored twice in the space of four first-half minutes to help Basel on the way to a 3-0 win over Valencia.
However, there were few on hand to witness the action after Basel, who were semi-finalists last season, were ordered to play behind closed doors following fan violence in the last-16 tie at Salzburg.
The 31-year-old Delgado opened the scoring in the 34th minute with a calm finish into the corner after being afforded too much space on the edge of the area.
He added a second in the 38th minute with Valentin Stocker creating the opportunity.
Stocker grabbed the third in injury time at the end of the match when he cut across Juan Bernat and lifted the ball over Vicente Guaita in the Valencia goal.
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