Nikola Vlasic's second-minute strike proved just enough for CSKA Moscow to cling on for a famous win over defending champions Real Madrid in Champions League Group G.
Vlasic pounced on a rare error by Toni Kroos to fire the opener and the Russians defended resolutely and even survived the bizarre injury-time sending-off of goalkeeping hero Igor Akinfeev, apparently for dissent.
Mariano, Karim Benzema and Casemiro all hit the woodwork for Real while Luka Modric and Raphael Varane were among those who missed easy chances to drag their side back into the game.
Ultimately, questions may be asked about the wisdom of Real boss Julen Lopetegui in starting with Modric on the bench with Gareth Bale and Sergio Ramos missing due to injury.
Elsewhere, Paulo Dybala scored a hat-trick as Juventus - missing Cristiano Ronaldo through suspension - beat Young Boys 3-0 in Turin to continue their perfect start to the new season.
The Bianconeri took the lead after five minutes when Dybala crashed in a volley.
The Argentinian doubled the lead just after half an hour, knocking home a rebound from Blaise Matuidi's shot, and completed his hat-trick after 69 minutes with a close-range finish.
Ajax battled to a 1-1 draw at Bayern Munich. Defender Mats Hummels headed Bayern into a fourth-minute lead. Ajax, though, were level after 22 minutes through full-back Noussair Mazraoui.