Reds Shocked
Liverpool's title defence begins with defeat, Chelsea on wrong foot
Holders Liverpool began their defence of the Champions League trophy with a defeat against Napoli on Tuesday, while one missed spotkick 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.
In a Group F 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.