Chelsea ensured they will be in Friday’s Europa Conference League draw despite a nervy 2-1 second-leg defeat to Servette in Switzerland.

When Christopher Nkunku scored early from the penalty spot, the Blues were 3-0 up on aggregate and seemingly cruising through their play-off tie with minimal fuss.

But Jeremy Guillemeno finished well before half-time to level it up on the night, before Enzo Crivelli headed home with 20 minutes remaining to set up a grandstand finish as Chelsea came under huge pressure.

Nicolas Jackson had a goal disallowed for offside and Cole Palmer then hit the bar, with the Blues unable to find the goal that would have given them breathing space, but they survived the significant scare to secure a 3-2 aggregate win.

Chelssea went close early through a 30-yard bullet from Enzo Fernandez, tipped brilliantly around the post by goalkeeper Joel Mall, before taking the lead on the night and, at that stage, seemingly ending the tie as a contest after 14 minutes.

Mykhailo Mudryk was given room to break into the penalty area down the left, and as he sought to nick the ball around Keigo Tsunemoto the defender stuck out a stray leg and sent Mudryk to the ground. Nkunku repeated his feat from the first leg and with a composed strike into the corner stuck Chelsea in front from 12 yards.

Servette clawed their way back to within two goals on aggregate on the half-hour mark. Dereck Kutesa drove through the heart of midfield and having beaten three Chelsea players slid the ball right to Guillemenot who took it in his stride and angled a shot across Filip Jorgensen and in.

Nkunku almost restored the lead immediately, getting on the end of Renato Veiga's through ball but was thwarted by Mall as he raced from goal to meet him. It was one of a number of smart saves made by Mall in the first half, with Noni Madueke also denied by a fine smothering block after going clean through.

Jorgensen saved from Kutesa in the final moments of the half as Servette threatened to reignite the tie before half-time.

Chelsea contained their hosts well until 18 minutes from time but received a shock when substitute Crivelli got on the end of Miroslav Stevanovic's cross to head past Jorgensen and set up a nervous finale.

Jackson was denied by a strong left from foot Mall in stoppage time, after he had already had one chalked off and Palmer was denied by the woodwork as Chelsea sought to salvage the result on the night, but they edged through despite the defeat.

Additional reporting by PA Sport.