Naples: Holders Liverpool began their defence of the Champions League trophy with a defeat against Napoli on Tuesday, while one missed spot-kick condemned Chelsea to defeat against Valencia and another came to Barcelona's rescue.
Liverpool survived a 1-0 defeat in Naples in the group stage last season to go on and win their sixth European Cup, and this time a 2-0 reverse at the San Paolo made them the first reigning champions to lose their opening game in the competition since 1994.
Both sides had chances in the Group E clash before the hosts won a late penalty with barely 10 minutes remaining when Jose Callejon went down under an Andy Robertson challenge.
Dries Mertens beat Adrian from 12 yards and substitute Fernando Llorente -- who played for Tottenham Hotspur against Liverpool in last season's final -- then took advantage of a rare defensive lapse by Virgil van Dijk to make it 2-0 in stoppage time.
Last season's Europa League winners Chelsea ensured it was two defeats out of two on the night for English sides as they lost 1-0 at home to Valencia. Also in Group H, last season's semi-finalists Ajax claimed an impressive 3-0 home win over Lille with two of their newest signings among the goals.
After a patchy start to the season, Barcelona will be relieved to escape from their trip to Borussia Dortmund with a 0-0 draw as Lionel Messi returned from injury as a second-half substitute. The home side will feel they should have won, but Marco Reus had a second-half penalty saved before Julian Brandt hit the bar late on.
Those two appear well placed already to progress from Group F after Inter Milan needed a stoppage-time Nicolo Barella goal to rescue a 1-1 draw against rank outsiders Slavia Prague.
In Group G, RB Leipzig won 2-1 at Benfica with Timo Werner bagging a brace before Haris Seferovic pulled one back. The atmosphere inside the newly renovated Stadio San Paolo was electric from the start as both sides attacked relentlessly from the opening whistle.
Napoli countered Liverpool’s established attacking trio of Mohamed Salah, Roberto Firmino and Sadio Manş with a lineup featuring four forwards- Lorenzo Insigne and Jose Callejon on the wings surrounding Dries Mertens and Hirving Lozano.
Salah was on full sprint from kickoff but couldn’t find a way past Napoli’s center back Kalidou Koulibaly. Liverpool goalkeeper Adriŕn in his Champions League debut denied Fabian Ruiz twice in one action before Lozano headed the second rebound into the net only to be whistled offside.
As dazzling as the offensive display was, the defense was just as impressive. Jošl Matip lunged to head away a cross intended for Lozano that seemed a sure goal then Ruiz sprinted back at the other end to intercept what would have been a tap-in for Salah.
The frantic pace continued, with Firmino heading just wide of the far post from a corner in the 44th. Possession in the first half was split exactly 50-50. The fireworks continued immediately after the break when Adrian hung in the air to deny a volley from Mertens with one hand at the far post.
There was a rare defensive mistake when Kostas Manolas gifted the ball to Salah in a great position but Napoli goalkeeper Alex Meret extended to glove the Egypt international’s shot wide.
It was only in the last 15 minutes that the pace slowed, with both teams visibly exhausted on a warm evening. Then Napoli found the breakthrough after Robertson was adjudged to have tripped Callejon in the area. Adriŕn lunged to his left and got a hand on Mertens’ penalty but couldn’t stop it.
In the final minutes, Napoli fans’ whistled so loud every time Liverpool had possession it was deafening, and it seemed to have an effect when Virgil van Dijk gifted the ball to Llorente, who rolled it past Adriŕn with ease.