Liverpool, Champions League runners-up last season, suffered a shock 4-1 defeat by Napoli in their opening game at the Diego Armando Maradona Stadium in Italy.
Jurgen Klopp Photo: PHOTOSPORT
Napoli were magnificent in the opening 45 minutes, going in 3-0 up at the break having opened up a woeful Liverpool defence at will.
Jurgen Klopp's team looked nothing like the side who reached the final last season, disorganised at the back and lacking any edge in midfield or attack.
Pressure is mountain on Klopp with Liverpool seventh in the Premier League with just two wins from six games.
Yesterday Chelsea sacked manager Thomas Tuchel.
Napoli have now beaten Liverpool on all three occassions they have hosted them in the competition's group stage and Luciano Spalletti's side will feel they have a real chance of getting out of a group that also features Ajax and Rangers.
Ajax beat Rangers 4-0.
Richarlison's first goals for Tottenham Hotspur helped them mark their return to the Champions League with a 2-0 victory over 10-man Olympique de Marseille in London.
The Brazilian forward, signed from Everton in the summer, struck twice in five minutes late on to secure three points that had not looked likely for the hosts.
Richarlison's brace glossed over a largely mediocre display by Tottenham who were second best against a lively Marseille until the French side had Chancel Mbemba sent off three minutes into the second half for a foul on Son Heung-min.
Richarlison Photo: PHOTOSPORT
Tottenham, who missed out on the Champions league for the past two seasons, did not register a shot on target in a lacklustre first half but Richarlison eventually ensured a perfect start for Antonio Conte's team.
They share top spot in the group with Sporting Lisbon who beat Eintracht Frankfurt 3-0.
Robert Lewandowski struck a hat-trick in his first Champions League game for Barcelona to power the Catalans to an emphatic 5-1 home win over Viktoria Plzen of the Czech Republic.
Lewandowski's old club Bayern Munich beat Inter Milan 2-0 with Leroy Sane scoring one goal and forcing an own goal.
-Reuters
