In Rotterdam, striker Sergio Aguero scored his 50th goal in European club competitions as Manchester City romped to a record 4-0 victory over Feyenoord in their Group F clash at De Kuip.
Defender John Stones bagged a brace of headed goals and Brazilian forward Gabriel Jesus netted the other as City inflicted the heaviest-ever home defeat in UEFA club football on the Dutch champions and former European Cup holders.
Aguero reached his milestone with a typically clinical finish from Kyle Walker's cross as City made a fast start to the game, scoring three times in the opening 25 minutes to stun their hosts and kill off the contest.
Feyenoord, playing in the group stages of the Champions League for the first time in 15 years, never seriously troubled City goalkeeper Ederson who had recovered sufficiently to play, albeit with a rugby-style scrum cap, after receiving a boot to the face from Liverpool's Sadio Mane in a 5-0 Premier League win on Saturday.
Elsewhere, Liverpool drew 2-2 with Sevilla at Anfield after going behind early while a double from Cristiano Ronaldo gave Real Madrid a routine 3-0 win over Apoel Nicosia of Cyprus. Porto lost 3-1 at home to Besiktas while Shakhtar Donetsk upset Napoli 2-1.
In Slovenia a flare fired from the stands came close to hitting the referee as Maribor played Spartak Moscow.
The nautical-style flare was fired from a sector packed with Spartak fans after around 15 minutes and arced over the pitch before landing near referee Denis Aytekin.
The official briefly stopped the Group E game, but it resumed shortly after.
The match finished in a 1-1 draw, as did the clash between Leipzig - making their European debut - and French champions Monaco.