The Blues had taken the lead midway through the first half thanks to Joao Pedro but Gianluca Scamacca equalised early into the second period and in the final ten minutes, Charles De Ketelaere struck a shot which was deflected past Robert Sanchez to hand the hosts all three points.

Five changes

With Cole Palmer left at home due to the club wanting to manage his workload and Liam Delap out injured, Chelsea were always going to make changes and there were five alterations to the side that drew 0-0 with Bournemouth.

Benoit Badiashile started in the heart of defence instead of Wesley Fofana and Josh Acheampong was introduced, with the teenager starting as right back.

Moises Caicedo's three-match ban doesn't apply to European fixtures so he was back, while Jamie Gittens started on the left flank and Joao Pedro replaced Delap up top.

It was clear early on that when we had the ball, the defence became a back three, with Badiashile moving to the left side and Marc Cucurella pushing on into a No.10 position as we looked to create overloads in the final third.

It was Atalanta who had the first chance of the game as some slick build-up play saw former Charlton Athletic and Everton winger Ademola Lookman burst into the box down the hosts' left but his shot from a tight angle was well saved by Rob Sanchez and De Ketelaere was unable to adjust his feet quick enough to divert the rebound in.

Atalanta controlled possession early on before we worked our way into the game. But then on 19 minutes we needed an outstanding last-ditch block from Acheampong to deny Lookman what looked to be a certain goal as he slid in yards from our goal, after Chalobah had already blocked Scamacca's initial effort.

Blues ahead

But it was the Blues who took the lead midway through the half. We were patient at a short corner and James did well to hold his run on to Enzo Fernandez's through ball, and his low left-footed cross was poked in by the diving Joao Pedro.

It was initially ruled out for offside but James was adamant he had held his run and after a VAR check, the goal was given.

Chelsea's man-to-man pressing of Atalanta when they had the ball was bearing fruit as the first half progressed, as we regularly ended the hosts' attacks in their own half and looked to build our own before the interval.

Chalobah, who was on a yellow card, was replaced at half-time by Fofana, and Chelsea were first to go close in the second period as James had an effort on the edge of the box blocked and then dragged the follow-up from 18 yards wide.

The hosts thought they had an equaliser soon after when Lookman stabbed home a cross from the right but the Nigeria international was clearly offside.

The early stages of the second half was a lot more end-to-end than the first and we immediately had another chance as Jamie Gittens struck a fierce shot from the corner of the penalty area, which Marco Carnesecchi had to parry away.

Level

But it was to be Atalanta who scored next. A cross from the right side was hung up to the far post and former West Ham man Scamacca leapt to head in from close range to make it 1-1.

The frantic nature of the game continued, as Scamacca had a shot blocked, Neto saw a dangerous burst into the penalty area snuffed out, Scamacca struck the wall with a free-kick and Sanchez had to parry another effort away as a crowd of players approached.

The momentum was with the hosts as we approached the hour, so Maresca opted to bring on Malo Gusto in place of Enzo in midfield and Alejandro Garnacho replaced Neto, as Chelsea appeared to switch to a more traditional 4-3-3 and Gittens moved to the right flank.

The substitutions initially helped shore up Chelsea out of possession as both teams struggled to break down the opposition. Garnacho cut in and forced a save with a right-footed shot but it was a routine stop for Carnesecchi.

Hosts ahead

But a lapse in concentration was ultimately punished as on 83 minutes, Atalanta took a quick free-kick and De Ketelaere was allowed to run into our box before his right-footed shot was deflected off the leg of Cucurella and past the diving Sanchez.

There was a late charge from Chelsea as first Garnacho cut inside from the left flank and struck a powerful 20-yard shot which Carnesecchi had to palm away, and then James sent a shot from the edge of the box wide as we entered four minutes of injury-time.

And with one of the final kicks of the game, Joao Pedro had a shot from Acheampong's knock-down saved but it was to no avail as the Blues return home empty-handed.

What it means

The Blues are now 11th in the Champions League table, with half of the teams having a game in hand and s due to play tomorrow.

With the top eight qualifying for the round of 16 automatically and those sides from ninth until 24th going into a play-off round, we still need to gain points from our final two matches against Pafos at Stamford Bridge (21 January) and away to Napoli (28 January) if we are to guarantee our progression into the knockout stages.

What's next

Chelsea will be back on home soil for the first time in four matches on Saturday, when we welcome Everton in a 3pm kick-off.

We will then be back on the road once more, this time in the Carabao Cup when we travel to Cardiff City a week today.

The teams

Chelsea: Sanchez; Acheampong, Chalobah (Fofana HT, Tosin 90), Badiashile, Cucurella; James, Caicedo; Neto (Garnacho 67), Enzo (Gusto 67), Gittens; Joao Pedro
Subs not used: Jorgensen, Merrick, Hato, Andrey Santos, Estevao, Buonanotte, George, Guiu
Scorers: Joao Pedro 25
Bookings: Chalobah 29

Atalanta: Carnesecchi; Bellanova (Zappacosta 17), Kossounou (Ahanor 71), Djimsiti, Kolasinac, Bernasconi; de Roon, Ederson (Pasalic 87); De Ketelaere, Scamacca (Krstovic 72), Lookman (Musah 87).
Subs not used: Sportiello, Hien, Samardzic, Scalvini, Brescianini, Zalewski, Maldini.
Scorers: Scamacca 55, De Ketelaere 83

Referee: Alejandro Hernández
Attendance: TBC