Chelsea strolled to a comfortable 4-1 win at Djurgarden in the first leg of their Uefa Conference League semi-final on Thursday to all but book their spot in the final.

In the other semi-final, Spain's Real Betis take a 2-1 lead into the return fixture against two-time runners-up Fiorentina.

First-half goals from Jadon Sancho and Noni Madueke put Chelsea in control in Sweden, before Nicolas Jackson grabbed a brace midway through the second period.

"It was (a perfect night), an important semi-final," Chelsea manager Enzo Maresca said.

"It's a good result, but we have the experience from the Legia Warsaw game, where we won 3-0 there and we struggled a little bit (Chelsea's only loss in the tournament came at home in the return fixture), so we need to be focused on the second leg."

Maresca's side have one foot in the final of the Conference League in their debut campaign in the third-tier European competition.

Lifting the trophy in the Polish city of Wroclaw on May 28 would add another continental title to the London club's haul of two Champions Leagues, a pair of Europa Leagues and two Uefa Cup Winners' Cups.

Their opponents, on the other hand, don't quite boast the same European pedigree, and in making the last four became the first Swedish side to play a semi-final in Europe since 1986-87.

To further add to Djurgarden's underdog status, coach Jani Honkavaara only had 14 senior players fit to call upon for the visit of the Premier League giants.

Chelsea took the lead via Sancho on 12 minutes as the winger collected a lofted pass in the box and slotted the ball past the goalkeeper before the retreating Marcus Danielson sliced his attempted clearance against his own arm and into the goal.

The goal settled Chelsea, who slowly got more accustomed to the artificial surface in Stockholm and began to dominate Djurgarden.

Madueke made that dominance pay two minutes prior to half-time when he opened up his body to feint a cross-goal shot with his left foot, before sweeping a first-time finish inside the near post.

The second leg ties will take place next Thursday. (AFP)