Arsenal stunned reigning champions Lyon and Barcelona set a new club record, while Bayern and Juventus also won.
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The UEFA Women's Champions League group stage started in stunning style as Arsenal ran out 5-1 winners at holders Lyon, while Barcelona, Bayern and Juventus were also victorious.
UEFA.com rounds up all the action.
Click on any scoreline to look back at all the action as it happened and watch highlights from midnight CET.
Arsenal were once dethroned as holders by then debutants Lyon in the 2007/08 quarter-finals, but this time the Gunners were the ones that stunned the defending champions. Never before had any team conceded five as holders in this competition, nor had Lyon ever done so in any competitive home match since FC Lyon became Olympique Lyonnais in 2004.
With Vivianne Miedema left out of Arsenal's XI, Caitlin Foord got the early opener, set up by Beth Mead. Frida Maanum made it two and although Melvine Malard pulled one back on 27 minutes, a superb Mead free-kick just before half-time made it 3-1.
The fourth and fifth arrived in the space of three minutes midway through the second half as Foord and Mead both added to their earlier goals. Lyon had never conceded four before in what was their 124th European fixture (and Arsenal's 99th).
Two late goals were enough for Juventus to make a winning start at Zürich. Juve, who made it to last season's quarter-finals after also beginning their group campaign with a victory in Switzerland at Servette FCCF, were dominant throughout but were not able to break through until the final 19 minutes.
Valentina Cernoia broke the deadlock as she collected a flick in the area to thread a shot under Lourdes Romero. Cernoia was then replaced by Barbara Bonansea who, five minutes from time, found the top corner after an initial effort was blocked.
27 October: Juventus vs Lyon, Arsenal vs Zürich
Linda Dallmann's strike sealed victory for Bayern as they came from behind to beat the Swedish champions. Maximiliane Rall missed a golden chance before Jovana Damnjanović's header was diverted on to the post, but it was the visitors who took a surprise 25th-minute lead when Loreta Kullashi nodded home.
Carolin Simon levelled matters when her cross from the right bounced past everyone and in. Dallmann got the winner not long before the hour when she tapped home after Damnjanović's header was saved. Bayern were largely comfortable from there but Mia Persson did hit the crossbar late on.
Seven different players got on the scoresheet as last year's beaten finalists started their campaign in emphatic style. Asisat Oshoala set up Patricia Guijarro and Aitana Bonmatí early on before getting on the scoresheet herself with a superb long-range strike.
Mariona Caldentey's solo effort made it four early in the second half, before she teed up Ana-Maria Crnogorčević for number five. Geyse Ferreira came off the bench to net the sixth against her former club and Clàudia Pina tucked home the seventh, before Caldentey brilliantly set up Oshoala for number eight. Geyse headed in the ninth to cap a memorable UEFA competition debut as Barcelona recorded their biggest ever European win.
27 October: Rosengård vs Barcelona, Benfica vs Bayern