Chelsea were grateful for their first-leg lead over Servette as they were beaten 2-1 on the night in Geneva but booked their place in the Europa Conference League draw courtesy of a 3-2 win on aggregate.

This was Chelsea's 299th game in European football. They have won everything there is to win on the continent - except this one, the newest competition.

They will hope this is the start of them completing the set again. In Switzerland, they extended their lead within 15 minutes as Christopher Nkunku scored from the penalty spot after Keigo Tsunemoto had taken down Mykhailo Mudryk inside the box.

This was Chelsea's first visit to Servette since the decade following the Second World War. Chelsea were in cruise control, but complacency allowed the hosts to get a foothold in the contest as Jeremy Guillemenot, once of Barcelona's academy, latched onto Dereck Kutesa's pass to steer his shot across Filip Jorgensen into the far corner on 32 minutes.

Noni Madueke, fresh from a deserved England call-up following his blistering start to the campaign, ought to have notched his fifth goal in three matches when he was played in by Marc Guiu but he telegraphed his finish as Joel Mall denied him.

Kutesa continued to cause problems as Jorgensen kept out his shot after another knifing run from left to right.

The second period initially lacked major incident with Chelsea controlling proceedings. There was even a nice moment for Tyrique George as the 18-year-old came off the bench to make his professional debut.

But that suddenly changed when two Servette substitutes combined, Miroslav Stevanovic's cross headed in by Enzo Crivelli after both Benoit Badiashile and Jorgensen lost their footing on 72 minutes.

It sparked an anxious final quarter of an hour which might have been far more serene when Cole Palmer was found by an Nkunku pass only to see his shot smack the crossbar.

There was still time for a final Servette chance. Gael Ondoua won the ball in front of Palmer as Julian von Moos set up Timothe Cognat but there was not enough bend on his shot.

Chelsea had the opportunities to put the tie to bed, but it didn't prove costly. Enzo Maresca continues to try and sell a number of first-team players, and while Friday could prove another busy day at the club, booking a spot in the Europa Conference League draw represents the first important milestone in his tenure.