Chelsea laboured to an unconvincing 2-0 win over Servette in the first leg of their Conference League play-off at Stamford Bridge, second-half goals from Christopher Nkunku and Noni Madueke sufficient to give Enzo Maresca’s side the lead in the tie.

It was the Italian head coach’s second game in charge but already signs of discontent were heard from home supporters, who booed the team off at the end of a first half in which they failed to muster a serious attacking threat against the side currently fifth in the Swiss league table.

It took Nkunku’s 50th-minute penalty, won thanks to the game’s first genuinely incisive pass played by Kiernan Dewsbury-Hall, to finally break down Servette, who had coped defensively with relative ease until that point and might have taken the lead through winger Dereck Kutesa.

Madueke came off the bench to score Chelsea’s second and hand them a healthy lead ahead of the return leg in Geneva next Thursday.

Maresca made nine changes to the team that lost to Manchester City on Sunday with only Moises Caicedo, who captained the team for the first time, and Nkunku remaining.

That meant full debuts for six summer signings, amongst them striker Marc Guiu who was inches from opening the scoring in the second minute, rounding the goalkeeper from fellow full debutant Dewsbury-Hall’s through pass but failing to reach the ball before it squirmed from his reach behind the goal.

Servette carried their own threat and broke through Chelsea’s lines when Kutesa played a one-two inside the box with Keigo Tsunemoto before streaking past Axel Disasi and striking a low effort that was deflected away by goalkeeper Filip Jorgensen.

Chelsea were relying heavily on their two wide forwards, Mykhailo Mudryk and Pedro Neto, but though both were frequently on the ball, neither player provided the delivery or penetration necessary to find a way in behind Servette.

There was more success when Mudryk tried to cut inside. Guiu held the ball up well for him midway through the first half giving the Ukrainian room to shoot, but he dragged his shot tamely wide of the post.

Nkunku sought a more central route through, intercepting a loose pass and charging through the middle to feed Mudryk, who slipped it wide for Neto to come inside and shoot left footed. His effort lacked bite and landed cleanly in the arms of Jeremy Frick, encapsulating Chelsea’s first-half labours.

One and a half matches into Maresca’s tenure, the team left the pitch to a smattering of jeers from home fans.

Chelsea’s play had been breaking down in wide positions, but in the second minute after the interval Dewsbury-Hall sought to play directly down the middle, finding the run of Nkunku who reached the ball before Frick and, though heading away from goal, was brought down. From the resulting penalty, he fired calmly into the corner for 1-0.

Guiu made a horrendous mess of an open goal, before Maresca sent on Cole Palmer in search of a creative glint.

Instead it was two other second-half substitutes who provided the goal, Enzo Fernandez launching the ball up the right wing for Madueke to streak onto it and lash the ball in at the near post to settle nerves.

Jorgensen saved well to his right from Jeremy Guillemenot after Chelsea gave the ball away in defence, before Tiemoko Ouattara cracked the bar as Chelsea survived gratefully with their two-goal lead in tact.