Real Madrid coach Manuel Pellegrini admits they struggled to match Lyon's physical approach in last night's 1-0 Champions League defeat.
A stunning second-half strike from Jean Makoun proved the difference at the Stade de Gerland.
Pellegrini was impressed by the French side's dogged display but remains confident of securing a place in the quarter-finals.
"This evening Lyon outmuscled us," Pellegrini said. "We just didn't know how to cope and obviously it wasn't a great result for us.
"We conceded a goal and failed to score one ourselves. We will have to be more disciplined in the second leg and do to them as they did to us this evening."
The result was the sixth successive defeat for Los Blancos in the knockout stages of the Champions League but Pellegrini has backed his side to end that run next month.
"I am certain that we can achieve that and win the tie," he added.
"I don't believe the same demons that have plagued the side in recent seasons have returned."