Chelsea avoided a late scare as they maintained their unbeaten record in the UEFA Conference League, defeating league leaders Copenhagen by a narrow margin.
The first half was evenly matched, but the Blues sprung into life in the second - with well taken goals by Reece James and Enzo Fernandez giving the Blues a solid lead. Copenhagen halved the deficit from a free kick, but struggled to break their opponents down for a good portion of the contest.
Enzo Maresca will have been happy with the way his side improved in the second half - despite conceding late in the match - and will focus on the second leg next week, where Chelsea will be expected to maintain their lead and progress into the next stage of the competition.
Story of the Match
After an unbeaten group stage, Chelsea made their return to European commitments, and bolstered their squad with more first team additions, including Cole Palmer, who begun his first Conference League match and looked to regain some confidence in front of goal.
Striker Shim Mheuka was rewarded with a full debut, getting the nod ahead of Christopher Nkunku. Tyrique George was also trusted on the wing - with Jadon Sancho and Pedro Neto both available off the bench if necessary.
There were also welcome returns for Trevoh Chalobah and Benoit Badiashile; the pair were both fit enough to make the away journey.
Enzo Maresca had praised Copenhagen ahead of the game, mentioning their strong league position as well as their success in this competition, defeating Heidenheim over two legs to reach the Round of 16 stage.
The atmosphere in the Parken Stadium was fierce from the first whistle - a consistent whistling hum and chants of 'who are ya?' filled the air. The hosts defended in a 5-4-1 shape whilst the Blues were content with keeping possession and finding openings in attack.
With Renato Veiga and Ben Chilwell both on loan for the remainder of the season, Malo Gusto was asked to fill in at left-back and often covered the flank. It allowed for Kiernan Dewsbury-Hall to move more centrally, slotting in alongside Palmer.
It was a tricky role for Gusto, who was eventually substituted midway through the first half after struggling with an injury. Marc Cucurella was named on the bench and was brought on in his place - much earlier than Maresca will have liked.
Chelsea had kept possession well, but couldn't find a way through Copenhagen's defence. The best chances in the half had come from the hosts - Amin Chiakha had several shots blocked, while midfielder William Clem saw his effort soar over the bar.
It was clear this was a match Enzo Maresca wanted to win - Levi Colwill and Christopher Nkunku were seen warming up at half-time, among others. The Blues remained the favourites to lift the trophy and had been handed a favourable route to the final, but couldn't afford to get complacent.
Both Colwill and Nkunku were introduced at the start of the half, as well as Enzo Fernandez. Fresh legs appeared to be the solution as the Blues took the lead after a minute - Reece James shooting from distance after Enzo Fernandez had released Cucurella with his first few touches of the ball.
Copenhagen looked for an instant response - Viktor Claesson was played through wonderfully, but the resulting finish bounced off the inside of the post and into the path of Robert Sanchez.
The match had sprung into life, and was a great contest from a neutral perspective with both teams energetic and searching for a goal.
It would be Chelsea that would find it - Cucurella and Nkunku did well to win the ball back, before Tyrique George picked out Enzo Fernandez in the middle. The Argentine placed a brilliant finish into the far corner to give the Blues a two-goal cushion.
The number of fouls increased towards the end of the game as both sides kept up the intensity. Chelsea were desperate to maintain their clean sheet, but were punished by a well taken free-kick - defender Gabriel Pereira was unmarked at the far post and headed past Sanchez to give Copenhagen their goal.
Poor marking from set plays has been a weakness to Enzo Maresca's side, and they were once again punished. Their only clean sheet in the competition came in the 8-0 demolition of FC Noah, and their habit of conceding goals has been a regular theme so far this year.
It was a late downside to an otherwise solid performance, as the Blues take a one goal lead back to Stamford Bridge for the second leg, where they will hope to avoid a shock upset.
The contrast between the first and second half demonstrated why Enzo Fernandez is such an important player for the Blues.
The midfielder had a part to play in each of his team's goals, and was crucial in linking play between defence and attack - something Chelsea struggled with in the first half.
His ability to play past the Copenhagen press as well as a solid range of passes to find his teammates in space is crucial, and was a key reason why the Blues are leaving Denmark with a victory rather than humiliating defeat.