Chelsea manager Enzo Maresca says he "trying to solve" his side's "habit" of conceding too many goals after a 2-1 defeat by a young Real Madrid side in Charlotte, in the final match of their United States tour.
First-half goals from Dani Ceballos and Brahim Diaz were enough for Madrid despite Noni Madueke's header as the Blues again looked vulnerable at the back.
They have conceded 12 goals across five pre-season games in America, going 4-0 down in two of those matches and winning just one.
Maresca said he addressed the "very high" defensive line with his players in one of his first meetings, which he said is a habit "from last season".
Ceballos followed in a deflected Lucas Vazquez shot to finish in the 19th minute.
And in the 27th minute Diaz rounded new goalkeeper Filip Jorgensen to score from a tight angle past the Dane, who made his first start at the Bank of America Stadium.
Chelsea pulled one back as Madueke headed in Enzo Fernandez's cross at the far post in the 39th minute.
Maresca made no substitutes at half-time but his tweaked team looked more solid as they played out a drab goalless second half where the best opportunity was a spurned one-on-one chance for Christopher Nkunku.
Carlo Ancelotti's side were still without a host of star players, but wide attacker Vinicius Jr excelled in the absence of Jude Bellingham and Kylian Mbappe, who are expected to train as early as tomorrow as both sides flew back to Europe immediately after the match.
Chelsea next face Inter Milan in their final friendly at Stamford Bridge on Sunday before their Premier League opener at home against champions Manchester City on 18 August.
Madrid next face Atalanta in the Uefa Super Cup in Warsaw on Wednesday 14 August, which pits the Champions League winners against the Europa League winners, as a curtain-raiser for European competitions.
Chelsea conceded 63 goals under Mauricio Pochettino in the league last season, an unwanted club record during the Premier League era.
That tendency not to press with intensity and allow quality players - like those at Celtic, Manchester City and Madrid on this tour - time on the ball to pick them off has continued.
Maresca said: "One of my first meetings with the squad was about the amount of goals we conceded last year with the defensive line very high.
"We are not working on defensive lines so high. It's a habit from last year, or years ago, I don't know.
"We are trying to drop the defensive line a little bit, usually about four or five metres, just to have some advantage.
"Last year, we already conceded many goals with this problem. Hopefully we can solve it very soon."
The former Leicester manager continued by explaining it is not an issue with his defence, which featured Reece James, Levi Colwill, Benoit Badiashile and Malo Gusto, but the team as a whole.
The Italian has also been attempting to implement his new system and style which has seen several individual mistakes leading directly to goals conceded in the United States.
Maresca has previously admitted to using his matches as "training sessions", without time to do tactical work in between all the travel and the five matches in 14 days in the high heat of the United States.
That instability must be resolved, he says, before Chelsea face Manchester City in their Premier League opener.
Brazilian superstar Vinicius Jr reminded the 55,000 crowd of mainly Madrid supporters of his class before Mbappe's imminent arrival.
This was Vinicius' first start in pre-season after his involvement in the Copa America and he put on a show for those in attendance, creating several chances alongside his typical work rate in pressing and making runs behind to test that high Chelsea defensive line.
He curled his first effort just wide, then forced a mistake in the box which led to a huge missed Diaz chance. His through ball assist gave another opportunity for the 25-year-old Morocco midfielder, which he dispatched.
Mbappe may soon become the focus, with England's star midfielder Bellingham also in the squad, but Vinicius remains one of the most exciting attackers in the world and a contender for this year's Ballon d'Or.
Hardworking striker Marc Guiu, 18, who was signed from Barcelona for £5m, has started all but one of Chelsea's pre-season matches.
Guiu showed promising signs in other matches, but was quiet against the highest level of opposition in European champions Madrid.
Alternative option Nicolas Jackson only did his first training session yesterday and Chelsea look short of options despite boasting a huge squad of 45 players.
Romelu Lukaku and Armando Broja, who was left out of the matchday squad despite being fit, look set to leave.
It leaves Nkunku, who finished the match up front, as the most likely option to start against Manchester City.
But the Frenchman has looked good in a midfield role in parts of Maresca's pre-season.
It's clear why Chelsea are looking to add to their options amid active talks to sign Atletico Madrid's Samu Omorodion, with interest alive in Napoli's Victor Osimhen.