The Champions League returned this week as last season’s runners-up Liverpool got off to a nightmare start in Naples, while Chelsea’s unexpected defeat away to Dinamo Zagreb proved Thomas Tuchel’s last stand.
Here, the PA news agency takes a look at what we learned from matchday one.
Nightmare in Naples
Liverpool took their stuttering Premier League form into Europe – and could probably count themselves lucky not to have been more than 3-0 down at half-time against Luciano Spalletti’s exciting side.
The Partenopei eventually ran out 4-1 winners in a raucous Stadio Diego Armando Maradona.
One result, of course, does not define a campaign, but Klopp – whose side host Ajax on Tuesday in their second group match – admitted the manner of the capitulation in Naples would lead to “lots of soul searching”.
Tuchel’s time to go
Chelsea’s 1-0 defeat at Dinamo Zagreb proved to be the last match of Tuchel’s reign as the Blues’ hierarchy sacked the German on Wednesday morning.
The German coach had presided over three defeats from seven matches in the new campaign, during which he questioned whether the squad had enough depth for the challenges ahead.
On the back of spending a one-window Premier League record £273million to revamp the squad, new Chelsea owners Todd Boehly and Behdad Eghbali expected more.
Brighton boss Graham Potter appears to be the club’s choice for the German’s replacement and could be in charge for the Blues’ next European tie at home to RB Salzburg next Wednesday.
Haaland rolls on
Erling Haaland scored another two goals as Manchester City thrashed Sevilla 4-0.
The Norwegian has scored 12 goals in seven games for his new club and a staggering 25 Champions League goals in just 20 appearances during his career.
Most of those goals came for Borussia Dortmund, who are the visitors in City’s next group match when the German side will try and halt Pep Guardiola’s free-scoring side.
Celtic and Rangers return
The Old Firm rivals made their long-awaited returns to the group stage of the competition, but neither managed to pick up a point in tough opening matches.
Celtic started brightly enough at home against reigning champions Real Madrid, but eventually were outclassed 3-0 in their first game back in the Champions League for five years. The Bhoys are off to Warsaw to take on Ukrainian side Shakhtar Donetsk next in a tie which is likely to be crucial for their hopes of progressing any further.
Rangers, meanwhile, went down 4-0 to Ajax in Amsterdam, as the Dutch side scored three times in the opening 33 minutes. Not an ideal start after a 12-year absence, but Napoli should expect a hot reception when they travel to Ibrox next week.
Lewandowski enjoys new surroundings
Poland striker Lewandowski took his personal Champions League tally to 89 as he plundered a hat-trick to help Barcelona sweep aside Viktoria Plzen 5-1 at the Nou Camp on Wednesday.
He may have turned 34 in August, but Lewandowski looks fresher than ever after his summer move from Bayern Munich – which is exactly where he is headed in matchday two for a mouthwatering heavyweight clash.
Typical late drama
The opening week of the Champions League continued providing the drama right through to the end of matchday one.
Atletico Madrid snatched a 2-1 victory over Porto at the Metropolitano Stadium – with all three goals coming during 11 minutes of stoppage time.
Mario Hermoso thought he had struck the winner only for Mateus Uribe to score from the spot at the other end to make it 1-1.
But there was still time for substitute Antoine Griezmann to nod home a winning goal. The Champions League is certainly back.