Liverpool 0-3 Napoli: Reds beaten as Harvey Elliott makes first appearance
Liverpool suffered a 3-0 loss to Napoli seven days before their domestic campaign begins against Manchester City in the Community Shield.
Lorenzo Insigne was involved in three goals at Murrayfield as Liverpool made it four pre-season games without a win.
The striker curled in the opener before setting up Arkadiusz Milik with a fizzing, low cross after half an hour.
And the rebound from his shot fell kindly for Amin Younes to complete the scoring after the break.
The Reds' new signing Harvey Elliott made his first appearance - as a substitute - following his arrival from Fulham earlier in the day, but it was a "painful" afternoon for Jurgen Klopp's team in Edinburgh.
Strong line-up but Liverpool left looking 'a bit foolish'
The European champions looked rusty, and defensive errors meant they were 2-0 down within half an hour.
Seven of the starting XI that beat Tottenham in the Champions League final in Madrid were in the team but Liverpool were still without key attacking trio Roberto Firmino, Mohamed Salah and Sadio Mane, as well as Brazilian goalkeeper Alisson. Those four are yet to play a minute during pre-season because of international commitments.
With their first competitive match against Premier League champions City looming, midfielder Georginio Wijnaldum admitted it was a "poor performance" from his team, who he said "were not 100% concentrated".
"It was not our best game," Wijnaldum told LFCTV. "The things we normally do right - pressing and playing good football - we didn't do.
"If you play like today it is really painful. We didn't do it as a team and made too many mistakes. It is all about getting the minutes but also about getting the results. We have to learn from it."
Scotland international Andy Robertson, playing in front of a home crowd at Murrayfield, added that Liverpool "looked a bit foolish" and urged his team-mates to "step it up massively" before Sunday's game at Wembley.
"We were miles off it and Napoli outplayed us," Robertson said. "It is something we need to look at because the season starts for real next Sunday. We were pressing in ones and twos when it is usually threes and fours. Sometimes we looked a bit foolish.
"We've got one more game before it gets competitive. It's not crisis meetings or anything like that. When the season comes round, I've got no doubt we will be ready. We need to start winning games."
Reds boss Klopp said there was no excuse for the defeat but admitted some of the players had "heavy legs" and is looking forward having most of this squad back on Monday.
"The start and finish were good, but in between we conceded simple goals," said Klopp.
"We need to do better. I don't want to look for an excuse - and Napoli started pre-season at the same time as us - but their season starts three weeks after us so they can train nice and smoothly, but we have to work hard in four weeks and sometimes you have heavy legs in games like this as a result.
"I knew before we started it would be exceptionally difficult this summer. From [Monday], we have everyone but Sadio Mane and that's when we can really start preparing."
Confident Elliott but error-ridden performance from Reds
Champions League hero Divock Origi squandered Liverpool's first chance of the match before keeper Simon Mignolet kept out efforts from Belgian duo Simone Verdi and Dries Mertens.
But when Joel Matip stood off Insigne and allowed him to drive into the box, the striker expertly curled the ball past Mignolet. Milik slid in to divert the ball into the far corner and double Napoli's lead 11 minutes later.
Liverpool needed a spark and some of the 65,000 fans in Murrayfield thought Wijnaldum had provided it but his effort was ruled out for a clear offside on the stroke of half-time.
A disgruntled Liverpool side were keen to make a difference in the second half as James Milner set the tone with a thumping tackle on the edge of the opposition area, but it was Napoli who scored again through Younes.
Klopp made wholesale changes throughout the second half but it was 16-year-old midfielder Elliott's introduction which sparked excitement.
He seemed unfazed by the occasion and his first touch was a confident one-two with Rhian Brewster which earned Liverpool a corner. In his 12-minute spell he showed glimpses of the potential which helped him become the youngest player to feature in the Premier League while with Fulham.
But Liverpool's best chances of the match came from two other substitutes - 19-year-old forward Brewster's cross was almost diverted into the net by a Napoli defender before Harry Wilson's long-range curler was palmed wide by the keeper.