Enzo Maresca’s naive tactics were exposed and his team made too many mistakes when playing defensively, but there was ONE silver lining for Chelsea: FIVE THINGS we learned after the Blues’ humiliating 4-1 defeat to Celtic

Chelsea were humiliated by Celtic in Indiana on Saturday as Enzo Maresca’s side fell to a 4-1 friendly defeat at Notre Dame Stadium.

Matt O’Riley, Kyogo Furuhashi, Luis Palma and Michael Johnston all found the net for the Hoops before a late Christopher Nkunku penalty put the Blues on the scoresheet.

This was Maresca’s second pre-season outing as Chelsea’s new manager and his tactics were humiliated by the Scottish side.

His first game in charge was a 2-2 draw against Wrexham earlier in the week.

Mail Sport’s Kieran Gill was at Saturday’s game and noted five things we learned from the action.

Matt O'Riley scored Celtic's first goal in Saturday's 4-1 win over Chelsea at Notre Dame

Matt O’Riley scored Celtic’s first goal in Saturday’s 4-1 win over Chelsea at Notre Dame

Naive Chelsea played like Big Angel’s Spurs

The number of times Celtic got past Chelsea’s high line with just one ball in behind was worrying, and was made worse by the lack of pressing from Enzo Maresca’s players, which gave their opponents plenty of time to pick out a pass.

That was exactly how Celtic made it 4-0, and it made us think of Ange Postecoglou’s Tottenham last season. Premier League rivals will be looking to expose Chelsea’s attacking line during the upcoming campaign because all it takes is the right ball and the right run to clear the way for them.

Chelsea’s right side was especially vulnerable when Reece James reversed into midfield as it left a gaping hole. Maresca has work to do in the defensive department because throughout this match, his players looked like mannequins. Although this is just pre-season, conceding four goals is embarrassing for Chelsea in any match.

This was Enzo Maresca's second game in charge of Chelsea and things need to improve a lot.

This was Enzo Maresca’s second game in charge of Chelsea and things need to improve a lot.

Nkunku was lively and played the full 90 minutes.

One positive for Chelsea is the sharpness of Christopher Nkunku, who was their liveliest attacker in an otherwise lacklustre first half.

After missing most of last season through injury, the 26-year-old Frenchman provided a threat up front and was the only player to complete the full 90 minutes.

Marc Guiu was also impressive, having been forced to the ground at times by Celtic defenders and still finding a way to keep the ball. Despite only being 18, the Spaniard is showing he can handle the physicality of the Premier League.

If he stays, of course, because Maresca wanted to see him in preseason before deciding whether to loan him out.

Nicolas Jackson has yet to train with the first team in the United States so Guiu is getting his chance to impress Maresca, and I’d say he’s making the most of it.

Christopher Nkunku was one of Chelsea's best players and scored his team's only goal of the match.

Christopher Nkunku was one of Chelsea’s best players and scored his team’s only goal of the match.

Schmeichel still has it

Kasper Schmeichel still has strength. The 37-year-old, who joined Celtic on a free transfer, was denying everything that came his way.

The two consecutive saves to deny Nkunku and then Carney Chukwuemeka were the best of the group.

Speaking of Denmark goalkeepers, Chelsea are on the verge of signing Filip Jorgensen from Villarreal for £20.7m on a seven-year contract.

He will act as competition for Robert Sanchez in the face of the possible sale of Djordje Petrovic, currently absent from the US tour due to injury.

Sanchez made a sensational save here, but looks unstable when trying to play out from the back, and often appears to play long.

Former Manchester City and Leicester goalkeeper Kasper Schmeichel has shown he is still a key player between the sticks

Former Manchester City and Leicester goalkeeper Kasper Schmeichel has shown he is still a key player between the sticks

Chelsea probably won’t play on such a bad pitch all season

Mail Sport received confirmation on Saturday that Cole Palmer, Conor Gallagher and Marc Cucurella will not be joining Chelsea’s squad in America, but that is not the worst news as it keeps them away from those pitches.

There were officials testing the bounce of the ball at Notre Dame Stadium and let’s just say it wasn’t the liveliest.

The playing surface here did not help the pass, pass, pass style of play that Maresca was trying to implement, as the ball was constantly stopping.

But that’s no excuse to feel ashamed of Celtic.

The playing surface at Notre Dame Stadium was well below the standards Chelsea are used to.

The playing surface at Notre Dame Stadium was well below the standards Chelsea are used to.

Mistakes are common

When Pep Guardiola took charge of Manchester City and ordered his team to play out from the back, they made mistakes.

The same will happen with Chelsea next season. We have already seen a mistake in pre-season when Benoit Badiashile gave the ball away to Celtic to score.

Chelsea fans should get used to having their hearts in their mouths at Stamford Bridge.