Frank Lampard suffered his first defeat as Chelsea manager as Leandro Damiao's late strike gave Kawasaki a 1-0 friendly win in Yokohama.
The pre-season contest had appeared to be heading for a goalless draw at the Nissan Stadium, until Brazil striker Damiao headed home with just four minutes to go.
Despite the result, however, Lampard will still have taken much from his side's run out in searing temperatures against the J-League champions, with midfielder Mason Mount once again catching the eye ahead of the new campaign.
How Lampard suffered first reverse
Lampard again opted to start with Mount - who recently signed a new five-year contract at Stamford Bridge - as part of a midfield three, and the 20-year-old impressed in a first period of few clear-cut openings.
Chelsea first-half XI
Caballero, Azpilicueta, Luiz, Zouma, Alonso, Kovacic, Jorginho, Mount, Kenedy, Pedro, Batshuayi
However, it was the introduction of Ross Barkley as one of several half-time changes that gave Chelsea's play some much-needed impetus in the second half, only for Shota Arai to thwart the visitors with a number of smart stops.
As the clock ticked down, though, the home team sensed a famous win, twice going close when first Damiao thumped the bar five minutes from time, before Willy Caballero - standing in for the ill Kepa Arrizabalaga - produced a brilliant one-handed save.
Chelsea second-half XI
Caballero, Zappacosta, Luiz, Christiansen, Emerson, Kovacic, Jorginho, Mount, Kenedy, Barkley, Giroud
But Chelsea - who brought on Christian Pulisic for his debut midway through the second half - did not heed the warning and from the resulting corner, Damiao was left totally unmarked at the far post to head home the winner.
Mount stakes a claim
Lampard clearly has great faith in his young charge, handing the England U21 international another start in midfield ahead of some more experienced players.
And the 20-year-old - who spent last season playing under the Chelsea boss while out on loan at Derby - did not let his manager down with another assured display in midfield.
Mount's passing, running off the ball and closing down were all impressive, with his best moment coming when he nearly opened the scoring with a delightful curler that was only just off target at the start of the second half.
And on his showings so far in preseason, Mount could very well have already played his way into Chelsea's starting XI for their opening Premier League clash at Man Utd on August 11.
Pulisic's long-waited Blues debut
Chelsea fans have been waiting some time to catch a glimpse of their new £57.6m midfielder from Borussia Dortmund, who they signed back in the January transfer window.
Twenty minutes into the second half at the Nissan Stadium, though, the US international finally entered the fray to make his Blues bow in place of the tiring Mount
However, in the short time he had on the field, the cultured Pulisic impressed with some neat touches in his position on the right of a midfield three.
'We were not clinical in front of goal'
Despite suffering his first loss as Chelsea boss, Frank Lampard still saw plenty of positives in his team's performance in Yokohama.
"Obviously we want to win matches no matter what," he said after the game. "But 10 days into preseason, having flown into Japan three days ago, brings up a lot of difficulties for us physically.
"And that is where I was very pleased with the players today, I thought they gave everything in strong humidity. Some good individual performances, some people finding their fitness and form. The normal things in preseason that take a bit of time, which is probably being clinical in front of goal, which we were not.
"But that comes and some small details, which we will work on. So I have no fears, I was happy with big parts of the performance."
'Zouma's a Chelsea player and I want him here'
Meanwhile, Lamaprd also spoke about Kurt Zouma's future, saying he wants the France defender - who spent last season on loan at Everton - to stay at Stamford Bridge this campaign.
"In terms of Kurt Zouma, he's a very good defender for us, very good player, very good person and professional," he said.
"I want him here, simple as that. We are competitive with the centre backs we have in the team and he had a very good season at Everton and I can understand why they want him.
"He's a Chelsea player and I want him."
July 23: Barcelona - Saitama Stadium, Japan
July 28: Reading - Madejski Stadium
July 31: RB Salzburg - Red Bull Arena, Salzburg
August 3: Borussia Monchengladbach - Borussia Park, Germany