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," he said.


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