Slavia Praha Women 0-9 Lyon Women - Highlights
Lyon women absolutely thrashed Slavia Praha 9-0 away from home
Lyon, the record eight-time Champions League winners, are expected to make short work of Group B and they showed no mercy to their hosts in the Czech Republic.
France star Kadidiatou Diani, a close-season signing from Paris Saint-Germain, netted twice for Lyon while 2018 Ballon d'Or winner Ada Hegerberg scored a penalty in the second half.
The Norwegian is the Champions League's all-time top scorer and that was her 60th goal in the competition.
There was also a brace for Canadian defender Vanessa Gilles, with Sara Daebritz, Danielle van de Donk, Eugenie Le Sommer and substitute Amel Majri getting their other goals.
Seen as one of the main threats to Barcelona's hopes of retaining the trophy, Lyon's next game will be at home to the Austrian side St Poelten.
"If everything goes the way we want it to go, we can go far in every competition," said the Lyon coach, Sonia Bompastor.
St Poelten were beaten 2-1 at home by Brann of Norway on Tuesday, with US-born Icelandic international defender Natasha Anasi scoring the winner for the visitors.