Christopher Nkunku's penalty helped Enzo Maresca earn his first win as Chelsea boss as the Blues secured a two-goal advantage against Servette in their Conference League play-off first leg.
A much-changed Chelsea side had been struggling to open up their Swiss opponents until Nkunku was sent sprawling by goalkeeper Jeremy Frick early in the second half.
The France forward, one of just two survivors from the Blues team that started the 2-0 home defeat by Manchester City on Sunday, picked himself up to score the first goal of the Maresca era from the spot.
The former Paris St-Germain player then celebrated in trademark fashion, external, producing a blue balloon which he inflated in front of jubilant Chelsea fans.
Chelsea should have doubled the lead moments later when Frick was caught dithering on the ball by 18-year-old Marc Guiu.
The Spain youth forward looked certain to score but lost his composure and Frick was able to get back and save.
However, substitute Noni Madueke did make it 2-0 with a ferocious 72nd-minute finish from a tight angle inside the penalty area.
Chelsea will be confident of finishing the job and advancing to the group stage of European football's third-tier club competition when they travel to Geneva for the second leg on 29 August.
BBC