Chelsea 2-0 Servette: Enzo Maresca does not get the relief he was looking for after a heavy week as Blues are booed off at half-time before Christopher Nkunku and Noni Madueke strikes

Enzo Maresca was not smiling when Christopher Nkunku scored his first official goal of his Chelsea era, not even when the Frenchman took a blue balloon from his sock and blew it up to celebrate.

Nor was it the case when Noni Madueke fired the ball into the top corner to give Chelsea the lead in the Conference League play-offs.

Only looks could kill as Chelsea’s head coach has higher standards than the football he saw against Servette, the visitors are fifth in the Swiss Super League.

Stamford Bridge have had some memorable European nights, but this will be good to rent space in the minds of their supporters for a long time to come. Maresca knew that too, and showed his frustration on the touchline as his team struggled until Nkunku’s penalty finally opened the scoring.

There were too many mistakes for Maresca’s liking, including Marc Guiu’s triple miss when he tried and failed to score three times in a row. There was nothing to fault in the 18-year-old’s effort, but when the goal is as open as it was, you need a striker to score.

The booing of the fans at half-time had told the story. Chelsea’s supporters thought they would win comfortably. Even without the exiled Raheem Sterling and Ben Chilwell, their starting line-up had been assembled at a cost of almost £500 million. Their bench cost a total of £375 million.

In the end they won and are halfway assured of European football for the coming season. The return leg will take place in Geneva next week, but Maresca expects more from this group.

“It was good that we didn’t give in, but we can learn,” he said. “They all need more time to learn the system better. For sure, 100 percent. But tonight it wasn’t easy for some of them in terms of physical condition.”

About Guiu’s miss, he added: ‘I just told him that he doesn’t like easy goals. He likes difficult goals! That’s normal. He’s the youngest in the squad. He’s going to score, that’s for sure.’

Better news was that Maresca was confident Cole Palmer had not suffered an injury, despite the Chelsea superstar grimacing as he walked down the tunnel holding his right hamstring in his hands.

Before the game kicked off, Stamford Bridge was introduced to the 36th signing of the Todd Boehly and Clearlake Capital era. Joao Felix walked away to a standing ovation after returning to Chelsea, this time as a £44.5million signing from Atletico Madrid rather than a loan.

It is his arrival, and that of Pedro Neto for £54m, that has led to Sterling being told to throw in the towel. Technically Sterling was at Stamford Bridge, his name still appearing next to number 7 on the back of a match programme sent to print before his banishment was revealed.

Neto was introduced to the crowd as ‘your new number 7’ and started for the first time in Chelsea’s blue. So much for a club that is, as rumour has it, terrified of the Premier League’s financial rules. They have not shied away from bringing in new players and two of their summer signings combined to create the first chance of the game inside 60 seconds.

Kiernan Dewsbury-Hall drove forward before collecting a pass behind Guiu, but Servette keeper Jeremy Frick raced to smother him first. Guiu is a physical specimen for his age and Chelsea will be hoping he proves to be a bargain from Barcelona for £5m.

Chelsea continued to search for a breakthrough. Neto’s pace down the right was nothing short of electric as he played with his opponent, defender Bradley Mazikou.

However, Servette were warned in the 15th minute when Dereck Kutesa rounded Axel Disasi and forced Filip Jorgensen into a fingertip save, leading to a series of corner kicks.

Chelsea fans were worried because their team was making mistakes. We saw Tosin Adarabioyo try to clear the ball but he shot it against Disasi and got a throw-in. We saw Benoit Badiashile play a blind pass back to Jorgensen which could have been an own goal.

In the 28th minute, Mykhailo Mudryk found himself through after Guiu had boxed in his Servette goalkeeper David Douline. Mudryk fired wide when he had the entire goal to aim at, one of many times he has frustrated fans here.

Then it was Neto’s turn. He fired a rocket from the right with his left foot, which landed in the grateful arms of Frick.

Inside Stamford Bridge, only Servette supporters could be heard: around 100 of them were topless and jumping in unison.

Before half-time, Maresca sent the entire reserve bench to the sidelines to warm up.

There were cheers as the whistle blew. But in the 50th minute Chelsea finally got a cheer from their supporters when Dewsbury-Hall’s ball found its way past Nkunku, who was outclassed by Flick. He stepped up to take the penalty himself, firing it into the bottom left corner for 1-0.

Guiu looked certain of another goal when he forced a foul on Flick with a high press. He blocked his clearance and the ball spun towards the six-yard box as Servette’s keeper scrambled to cover the gaping goal.

What followed were three shots from Guiu, none of which went in. His first was grazed, allowing Flick to save. His second was aimed at the keeper. His third was blocked by Yoan Severin.

With that, Maresca brought on Madueke, Fernandez and Palmer, who played up front. In the 76th minute, two of those substitutes doubled the lead. Fernandez played a ball past Madueke, who fired it past Flick to give Chelsea the lead in this two-legged tie.