Chelsea were punished by a clinical Celtic team at Notre Dame Stadium as the Scottish champions ran out 4-1 winners.
The second match of our USA Tour saw us face a Celtic team who were playing their fifth game of pre-season and entered the contest on the back of beating Premier League champions Manchester City in their last match.
Chelsea created a number of chances in both halves but goals from Matt O'Reily, Kyogo Furuhashi, Luis Palma and Mikey Johnston helped Brendan Rodgers' side to victory, with Christopher Nkunku adding a late consolation from the penalty spot.
Two changes
There were two alterations to Maresca's starting line-up, as Wesley Fofana made his first start in more than a year in place of Tosin Adarabioyo and Mykhailo Mudryk replaced academy graduate Tyrique George.
The Blues started incredibly brightly and almost scored inside 15 seconds when some neat passing saw Marc Guiu turn his defender midway through the half and slip the ball through to Carney Chukwuemeka, but his touch was a little heavy and the defender was able to slide in and make a last-ditch tackle.
Chelsea's bright start continued when Mudryk's deflected cross was headed goalwards by Nkunku from ten yards but Kasper Schmeichel palmed the ball away.
Minutes later and the former Leicester City goalkeeper made a good double-save. Noni Madueke's low cross was diverted goalwards by Nkunku but Schmeichel saved and then also stopped Chukwuemeka's follow-up with his feet, with Nkunku slicing the third effort wide.
A relentless opening ten minutes saw Celtic also almost score an opener themselves. The Scottish champions released Kyogo and his low shot at the near post was well saved by Robert Sanchez.
The Chelsea goalkeeper then had to push away a long-rage effort from Reo Hatate and the end-to-end nature of the game continued when the Spaniard saved James Forrest's shot at the near post.
Opening goal
Celtic, who start their league season next weekend, did take the lead on 19 minutes when a short corner from the right resulted in O'Riley slotting the ball into the far bottom corner from 12 yards out.
Chelsea almost responded immediately when Guiu turned in the box and forced Schmeichel into another save from close range.
Celtic were looking to play the ball in-behind the Chelsea defence and would have had a second when Maeda was released on the left flank and then crossed for Kyogo but for Sanchez leaping across goal to dive and expertly save the forward's shot from point-blank range.
The second goal did arrive just after the half an hour mark though when O'Reily got in behind the defence and slid the ball across to Kyogo to tap in from inside the six-yard box.
Madueke was carrying a threat on the right flank and he crossed for Chukwuemeka, who dribbled past a couple of defenders and had a right-footed shot saved by Schmeichel.
Instant impact
The second half began in a similar fashion to the first, as Chelsea almost scored immediately. Guiu outmuscled his defender before forcing Schmeichel into a good save. Substitute Raheem Sterling then hit the far post with the follow-up shot.
Sterling created another good chance for Madueke but the winger failed to make clean contact with his shot from 18 yards out.
Sterling was having a good impact following his arrival and forced Schmeichel into another good save, with Guiu then unable to bundle the ball into the net as it trickled wide.
Double blow
However, the result was effectively guaranteed when Celtic scored twice in the space of three minutes.
A mistake from Benoit Badiashile presented Luis Palma with Celtic's third goal and then a ball over the top released Johnston and he made it 4-0.
Chelsea did scored a consolation goal in the final minutes when Sterling was brought down in the penalty box by Colby Donovan and Nkunku sent substitute Viljami Sinisalo the wrong way from the spot.
Next up
Chelsea's focus now turns to Wednesday's match against Club America at Mercedes-Benz Stadium in Atlanta, with tickets still available here.
You can also watch it on the official Chelsea website and app for £4.99. Learn more here.
The teams
Chelsea's starting XI: 1 Robert Sanchez; 24 Reece James (C), 5 Benoit Badiashile, 29 Wesley Fofana, 6 Levi Colwill; 45 Romeo Lavia, 17 Carney Chukwuemeka, 18 Christopher Nkunku; 11 Noni Madueke, 38 Marc Guiu, 10 Mykhailo Mudryk.
Substitutes: 4 Tosin Adarabioyo for Fofana 46, 16 Lesley Ugochukwu for Chukwuemeka 46, 7 Raheem Sterling for Mudryk 46, 39 Andrey Santos for Lavia 67, 27 Malo Gusto for James 67, 41 Angelo for Madueke 79, 47 Lucas Bergstrom for Sanchez 80, 40 Renato Veiga for Colwill 80, 32 Tyrique George for Guiu 86
Unused substitutes: 50 Eddie Beach, 34 Josh Acheampong, 21 Ben Chilwell, 19 Armando Broja
Goal: Nkunku 89