Holders Real Madrid slumped to a shock 1-0 defeat at CSKA Moscow in their Champions League Group G clash — after falling behind inside two minutes.
Nikola Vlasic fired the Russians in front after only 65 seconds.
Real Madrid hit the crossbar in the first half through Casemiro, but, despite plenty of second-half pressure, the visitors, now winless in three games, could not find a way back into the match.
CSKA goalkeeper Igor Akinfeev was sent off for two cautions during stoppage-time.
Also in Group G, Roma thrashed Viktoria Plzen 5-0, with Edin Dzeko scoring a hat-trick.
Dzeko gave the Italians an early lead after just three minutes and added a second five minutes before the break.
Cengiz Under made it 3-0 after 64 minutes, with Justin Kluivert adding a fourth before Dzeko completed his treble with a header from a corner in stoppage-time.
Group F leaders Lyon came from two goals down to draw 2-2 at home against Shakhtar Donetsk.
Brazilian Junior Moraes had struck either side of half-time to seemingly put the Ukranians in control.
However, Moussa Dembele started the comeback with 20 minutes left and defender Leo Dubois equalised just two minutes later.
Ajax battled to a 1-1 draw at Bayern Munich to keep themselves ahead of the Germans at the top of Group E on goal difference.
Defender Mats Hummels headed Bayern into a fourth-minute lead.
Ajax, though, were level after 22 minutes through full-back Noussair Mazraoui.
In the same group, Benfica overcame the dismissal of defender Ruben Dias at the end of the first half to win 3-2 at AEK Athens.
Haris Seferovic put the Portuguese side in front after six minutes, with left-back Alex Grimaldo heading in a second on the quarter-hour mark.
AEK hit back with two goals in the space of 11 second-half minutes from striker Viktor Klonaridis to draw level just after the hour.
Benfica, though, got themselves back in front with 16 minutes left through substitute Alfa Semedo.
