Chelsea subs: Kepa, Caballero, Zouma, Emerson, Chilwell, Gilmour, Kante, James, Ziyech, Pulisic, Havertz, Abraham.
Chelsea starting XI: Mendy, Rudiger, Christensen, Azpilicueta, Alonso, Hudson-Odoi, Jorginho, Werner, Kovacic, Mount, Giroud.
Atletico Madrid subs: Grbic, San Roman, García, Sánchez, Torreira, Kondogbia, Lodi, Vitolo, Camello, Dembele.
Atletico Madrid starting XI: Oblak, Llorente, Savic, Felipe, Hermoso, Saul, Koke, Lemar, Correa, Joao Félix, Suárez
Stat: Chelsea were one of only four teams to win all three of their away games in this season's group stages, alongside Atalanta, Barcelona and Juventus; they also scored more goals on the road than any other side (10). However, their last away win in the knockout stages of the competition dates back to March 2012 against Benfica (1-0).
Stat: Chelsea were trailing for a grand total of four minutes during this season's UEFA Champions League group stages, less than any other side. Also, only Manchester City (1) conceded fewer goals than the London side (2) in the group phase.
Stat: Atlético Madrid scored only seven goals in six games in this season's group stages, the lowest tally amongst the 16 remaining sides in the competition.
Stat: The overall head-to-head between Atlético Madrid and Chelsea in European competition is perfectly balanced, with two wins each, three draws and 11 goals each.
Welcome to tonight's live coverage of the UEFA Champions League round of 16 tie between Atletico Madrid and Chelsea from the National Arena in Bucharest. Kickoff is at 8pm UK time.
Chelsea give the ball away and Joao Felix drives through a big gap in midfield and is fouled by Mount. The referee has no choice but to book the Chelsea midfielder.
We are underway as kick us off! Tonight's referee is Felix Brych.
That card for Mount means that he will miss the second leg for Chelsea.
Danger! Atletico press high with real intensity and force Azpilicueta to play the ball back to Mendy, whose touch is heavy and goes to Suarez. The striker doesn't go down even though there may have been a little contact. He is forced wide and it comes to nothing but Mendy's heart would have been in his mouth there.
Chelsea have an attack as Azpilicueta steps forward and delivers a cross towards Alonso at the back post but Lllorente does very well to head clear the danger for Atleti.
Chelsea win a corner on the right and Mount delivers an outswinger into the area but his delivery is poor and Suarez heads clear at the near post.
Atletico press high again and Jorginho gives the ball away as he panics under pressure. Saul finds Felix on the left to cross towards Correa but Alonso defends well on the back post.
Atletico attack well again and Hermoso plays a nice diagonal behind Hudson-Odoi for Lemar. The French winger, playing asa wingback tonight, cushions a cross into the area but Mendy claims well.
Chelsea have a spell of possession with Atletico sitting deep in almost a 6-3-1 shape. Christensen steps forward to receive and square pass 35 yards from goal but skies a shot high and wide of goal.
Llorente plays a nice one two with Correa on the Atleti right and Alonso cynically fouls Llorente and is lucky to avoid a card.
Chelsea get themselves in a mess in the left corner and Rudiger and Alonso don't deal with the danger and are both taken out by Suarez to drive along the byline and so nearly pick out Lemar at the back post.
Close! Chelsea now have a good attack as Hudson-Odoi finds Mount running to the byline and the midfielder drills a low across into the area which is no nearly converted by Werner, who could arguably have slid for the ball.
Penalty shout! Kovacic finds Werner, who attempts a one-two with Giroud and as he runs into the area, he goes down under a little contact by Correa. No penalty says referee Felix Brych.
Chelsea enjoy a good spell of possession after Atletico carelessly give the ball away in their own half. Werner gets a switch of play and wins a corner when his low cross is deflected away.
Chelsea take the corner short as Mount finds Hudson-Odoi, who finds Jorginho. The Italy international tries to find Mount's run with a slide rule pass but it's just too strong. Good idea though.
The Blues have has 72% of the possession so far but Atletico won't care as they are allowing a lot of the possession in less dangerous areas.
Lemar overruns the ball as he dribbles but is fouled by Mount. The Chelsea midfielder has to be careful after his earlier caution.
Chelsea play some good stuff as Kovacic carries the ball forward and plays a one-two but when Atletico clear the ball, it falls to Alonso to drive a low shot for Oblak to comfortably save.
Kovacic finds Alonso on the left and he delivers a lovely cross towards Giroud, who gets across his marker and heads towards goal but straight at Savic inside the six yard box.
Chelsea again have a long period of possession but Jorginho takes too long to cross and later, his slipped pass for Hudson-Odoi's dart into space is overhit.
The game takes a bit of a lull with lots of throw-ins. When Chelsea get it down to play, Jorginho tries a through ball but is runs straight through to Oblak.
Atletico have a good opening as Suarez plays the ball out to Lemar, who beats Hudson-Odoi to the 50:50 but he tries and fails to get the ball back to Suarez when Joao Felix had made a superb run. It doesn't seem like Lemar saw the movement of Felix.
At this stage, Chelsea have had 4 shots to just one for Atletico.
Jorginho has time and space for Chelsea and sees Hudson-Odoi's run behind Lemar but he overhits his pass and it runs out for a goalkick.
Save! Mount nutmegs Koke and does well to set up Werner to shoot from the left of the box and it draws a smart save out of Oblak.
Chelsea launch a fast counter attack with Giroud's layoff setting things in motion. The ball switches out to the left to Alonso and his cross finds Mount at the back post he gets caught in two minds and ends up doing a sidefoot cross straight out for a goalkick. That was a decent opening to say the least.
HALF TIME. Atletico Madrid 0-0 Chelsea. The away team have been slightly better aside from nearly committing goal-costing errors in the openings moments. Join us in 15 minutes for the second half.
The fourth official indicates one minute of additional time to be played.
Mount and Hudson-Odoi combine really well on the right for Chelsea but Mount can't get the ball into the area as Hermoso blocks the low cross away for a corner. Mount delivers but Azpilicueta fouls his marker so the danger is ended.
The second half is underway with no changes made by either coach.
Atleti get a corner after Azpilicueta heads behind when Mendy didn't expect a back pass. Lemar delivers but Saul is blown up for a high boot.
Alonso's cross is blocked by Correa and Chelsea have a corner. Mount plays it short and Hudson-Odoi delivers well but Atletico again defend well as Felipe clears with Chelsea players ready to pounce.
Mount does some sublime work as he beats a couple of players and slides a pass down the side for Werner in a great area but the German forward can't find Giroud's run as his final pass is very poor once again.
Hudson-Odoi cuts inside Lemar for Chelsea but when he shoots left footed at goal from 25 yards, Saul blocks well and Oblak claims the ball as he hang in the air.
Suarez strikes a shot for Atletico and its deflected away. The ball comes into the area and
Rudigers heads away.
Atletico now have an opening as they counter attack and speed but when the ball falls to Felix with his back to goal, he tries an acrobat effort and it goes over the bar.
Suarez is rolling around claiming Kovacic elbowed him in the face. That's the third time he has been rolling around on the ground in this half with another one also play acting.
Llorente is booked for hauling back Werner as he was about to launch a counter.
Jorginho cleans out Felix and is carded. He will miss the second leg.
Disallowed goal! Giroud with the finish but it was offside. But was it? VAR is taking a look.
GOAL! GIROUD! VAR rules that Giroud's acrobatic overhead kick past Oblak will count as it wasn't Mount who played the ball but instead Hermoso. As it came off a defender it can't be offside.
Chelsea make a double change as Kante replaces Kovacic and Ziyech replaces Mount.
Correa has a powerful shot for Atletico who suddenly have to attack now. Christensen blocks well though and Ziyech and Werner lead a breakaway which relieves some pressure for Chelsea.
Rudiger shields a ball out for a goalkick for Chelsea against Suarez and he takes offence to the Uruguyan grabbing his leg. Rudiger is lucky to escape a card for his reaction.
Reece James comes on to replace Hudson-Odoi for Chelsea to solidify things.
Atletico made a triple change as Torreira replaces Correa and Dembele comes on in place of Felix in attack and Lodi takes the place of Saul.
Werner is sent scurrying away on a counter attack for Chelsea but he shoots from a very narrow angle into the side netting with no real support around him.
Vitolo comes on to replace Hermoso for Atletico as they look for a goal.
Chelsea make their fourth and fifth changes as Havertz and Pulisic are introduced in attack. Werner and Giroud go off.
Chelsea look very comfortable here with nothing much happening in the match here with Atletico lacking ideas. There has basically been no response to going behind.
FULL TIME. Atletico Madrid 0-1 Chelsea. Giroud's 72nd minute goal separates the sides after a solid display by Thomas Tuchel's team. A strong defensive display and a deserved win.
Koke tries a long freekick from deep for Atletico but James ducks and lets it run out for a throw-in to waste some time and frustrate the hosts.
Chelsea try to waste time in the corner but Alonso takes a foul throw. At least it's miles from his own goal.
Chelsea try to break but Lemar catches Pulisic with a late challenge and is shown a yellow card.
The fourth official indicates six minutes of additional time to be played.
Chelsea try to break but Azpilicueta can't find Havertz breaking into the box. It was a half chance but Atleti are quite open since taking off Hermoso.