Eintracht Frankfurt marked their Champions League debut with a 3-0 home defeat by Sporting Lisbon, while Ajax overpowered Rangers 4-0 in Wednesday's group stage early kick-offs.
Europa League winners Frankfurt have previously been in the European Cup, losing the 1960 final 7-3 to Real Madrid, but have never before appeared in the Champions League version of Europe's top club competition.
They were undone by two quick goals midway through the second half. Sporting's English forward Marcus Edwards was fortunate with a deflected effort for the first but showed great skill to set up Francisco Trincao for the second.
Nuno Santos added a third for Sporting's first ever win in Germany.
The hosts earlier had a scare in the 12th minute when Edwards was adjudged to have been tripped in the box by Christopher Lenz. But the referee reversed his decision after video review.
The Germans, without injured captain Sebastian Rode, were backed by a passionate crowd and had their chances in the Group D opener. But the last pass was missing on too many occasions.
Scotland's Rangers, beaten by Frankfurt in last season's Europa League final, also lost badly on their return to the Champions League after a 12-year absence.
Ajax sold a host of top players in the window just closed but still showed lots more quality than Dutch coach Giovanni van Bronckhorst's Rangers.
Edson Álvarez, Steven Berghuis and Mohammed Kudus all scored in the first half in Amsterdam as Ajax made a strong start to Group A. Steven Bergwijn netted a fourth late on.
This season's group stage began on Tuesday with holders Real winning 3-0 at Celtic. German coaches Thomas Tuchel and Domenico Tedesco meanwhile were sacked after their Chelsea and RB Leipzig sides lost.
