The very best Hollywood scriptwriter would have struggled to have penned it better and although Bafetimbi Gomis grabbed an equaliser after 83 minutes, Real managed to take something away from the Stade Gerland for the first time in four visits.
GEAR:Up to £15 off Champions League kits through Kitbag. Free delivery on orders over £50
Nine times winners Real have gone out in the first knockout round in each of the last six seasons, including here in France's third city last year, but after the swiftest of big-stage cameos they are now in the driving seat.
Benzema, who helped Lyon win four Ligue 1 titles before joining Real in 2009, wriggled through in the box to slot home after 65 minutes. After the match the Frenchman gave his shirt to some adoring Lyon fans who forgave him for doing his duty.
LIVE:Our interactive coverage as it happened
"It's a great result because we are away from home, it was an important goal for the team. It's a really, really good moment," the striker said, eyeing the return leg on March 16.
"I didn't celebrate, I respect everyone here. It's the first time I've scored a goal so quickly."
Real coach Jose Mourinho rarely stays out of the limelight and his decision to use Benzema as an impact substitute rather than start him on his former ground paid dividends, even if he was more bothered about a penalty not given for handball.
FOUR EYES
"There are four eyes (between the referee and his goal-line assistant). It could be decisive. Let's hope it does not cost Real Madrid qualification," said the Portuguese.
"I feel it was a real Champions League match with all the difficulties involved in that. I'm hopeful of course, everything is open. Lyon are a good team, they have good players, a good coach. But it's 1-1 and we play at home."
Lyon made the brighter start with lively Brazil winger Michel Bastos, who will miss the Bernabeu game because of suspension, constantly troubling Real's backline.
Gomis was glad he finally got on the scoresheet with a tap-in after his 34th minute effort with the goal gaping was deflected over following a Bastos cross which goalkeeper Iker Casillas failed to gather on the slippery surface.
Real had others chances too in the rain, Cristiano Ronaldo forcing Hugo Lloris into a smart save with a free kick in a rare moment of class from the off-colour winger.
The Portuguese though did later hit the post with another free kick and Sergio Ramos rattled the bar with a header soon afterwards.
Lyon boss Claude Puel, whose side reached the semi-finals last term, thinks their strange jinx over Real can continue.
"It's a good result tonight. We know what we have to do in three weeks," he said.
"We finished stronger than them and it's good that we levelled with a team like that. We wanted to avoid conceding but... we have been left with an opportunity to qualify. We know we'll have chances there."
