Lyon made the most of some woeful goalkeeping by Barbora Votikova to beat Paris Saint-Germain 3-2 at home in a lively women's Champions League semifinal first leg on Sunday.
Catarina Macario's double and a penalty by Wendie Renard, who became the first player to make 100 appearances in the competition, gave the seven-times champions a slight edge ahead of the return leg in Paris next Saturday.
PSG, who paid the full price for two Votikova blunders, scored through Marie-Antoinette Katoto and Paulina Dudek.
Votikova, however, partly made up for her mistakes with a decisive save to deny Ada Hegerberg six minutes into stoppage time.
PSG went ahead on six minutes when Katoto beat Christiane Endler at the near post after dribbling around a slow Renard.
Lyon, however, levelled through Renard, who slotted in a penalty after Melvine Malard was brought down by Votikova in the 23rd minute.
Hegerberg's soft first touch to collect a woeful goal kick by Votikova allowed her to set up Macario with a delightful through pass for Lyon's second goal in the 34th minute.
Votikova's nightmare continued after the break when she failed to control the ball amid a mix-up with her defenders, allowing Macario to tap in from point-blank range five minutes into the second half.
PSG pulled one back in the 58th minute when Dudek scored a penalty after a handball by Malard.
The winners after both legs will face either Barcelona or Wolfsburg.
Defending champions Barca demolished Wolsfburg 5-1 in their first leg on Friday.